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21109680 = 2433529337
BaseRepresentation
bin101000010000…
…1101110110000
31110201111001000
41100201232300
520401002210
62032242000
7344300154
oct120415660
943644030
1021109680
1110a09019
1270a0300
1344b1547
142b37064
151cbeac0
hex1421bb0

21109680 has 160 divisors (see below), whose sum is σ = 75441600. Its totient is φ = 5419008.

The previous prime is 21109679. The next prime is 21109687. The reversal of 21109680 is 8690112.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21109687) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 62472 + ... + 62808.

It is an arithmetic number, because the mean of its divisors is an integer number (471510).

Almost surely, 221109680 is an apocalyptic number.

21109680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21109680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37720800).

21109680 is an abundant number, since it is smaller than the sum of its proper divisors (54331920).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21109680 is a wasteful number, since it uses less digits than its factorization.

21109680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 388 (or 376 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 21109680 is about 4594.5271791557. The cubic root of 21109680 is about 276.3718994109.

Adding to 21109680 its reverse (8690112), we get a palindrome (29799792).

The spelling of 21109680 in words is "twenty-one million, one hundred nine thousand, six hundred eighty".

Divisors: 1 2 3 4 5 6 8 9 10 12 15 16 18 20 24 27 29 30 36 40 45 48 54 58 60 72 80 87 90 108 116 120 135 144 145 174 180 216 232 240 261 270 290 337 348 360 432 435 464 522 540 580 674 696 720 783 870 1011 1044 1080 1160 1305 1348 1392 1566 1685 1740 2022 2088 2160 2320 2610 2696 3033 3132 3370 3480 3915 4044 4176 5055 5220 5392 6066 6264 6740 6960 7830 8088 9099 9773 10110 10440 12132 12528 13480 15165 15660 16176 18198 19546 20220 20880 24264 26960 29319 30330 31320 36396 39092 40440 45495 48528 48865 58638 60660 62640 72792 78184 80880 87957 90990 97730 117276 121320 145584 146595 156368 175914 181980 195460 234552 242640 263871 293190 351828 363960 390920 439785 469104 527742 586380 703656 727920 781840 879570 1055484 1172760 1319355 1407312 1759140 2110968 2345520 2638710 3518280 4221936 5277420 7036560 10554840 21109680