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21131800 = 2352196783
BaseRepresentation
bin101000010011…
…1001000011000
31110202121101021
41100213020120
520402204200
62032532224
7344421514
oct120471030
943677337
1021131800
1110a236a8
1270b1074
1344bb631
142b41144
151cc641a
hex1427218

21131800 has 96 divisors (see below), whose sum is σ = 53121600. Its totient is φ = 7793280.

The previous prime is 21131797. The next prime is 21131813. The reversal of 21131800 is 813112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 254559 + ... + 254641.

It is an arithmetic number, because the mean of its divisors is an integer number (553350).

Almost surely, 221131800 is an apocalyptic number.

21131800 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 21131800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26560800).

21131800 is an abundant number, since it is smaller than the sum of its proper divisors (31989800).

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

21131800 is a wasteful number, since it uses less digits than its factorization.

21131800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 185 (or 176 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 16.

The square root of 21131800 is about 4596.9337606713. The cubic root of 21131800 is about 276.4683987790.

Adding to 21131800 its reverse (813112), we get a palindrome (21944912).

The spelling of 21131800 in words is "twenty-one million, one hundred thirty-one thousand, eight hundred".

Divisors: 1 2 4 5 8 10 19 20 25 38 40 50 67 76 83 95 100 134 152 166 190 200 268 332 335 380 415 475 536 664 670 760 830 950 1273 1340 1577 1660 1675 1900 2075 2546 2680 3154 3320 3350 3800 4150 5092 5561 6308 6365 6700 7885 8300 10184 11122 12616 12730 13400 15770 16600 22244 25460 27805 31540 31825 39425 44488 50920 55610 63080 63650 78850 105659 111220 127300 139025 157700 211318 222440 254600 278050 315400 422636 528295 556100 845272 1056590 1112200 2113180 2641475 4226360 5282950 10565900 21131800