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28710640 = 2457167307
BaseRepresentation
bin110110110000…
…1011011110000
32000000122121001
41231201123300
524322220030
62503211344
7466015330
oct155413360
960018531
1028710640
111522a802
129746b54
135c4315a
143b550c0
1527c1cca
hex1b616f0

28710640 has 80 divisors (see below), whose sum is σ = 76995072. Its totient is φ = 9752832.

The previous prime is 28710629. The next prime is 28710641. The reversal of 28710640 is 4601782.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-3 number, since 3×287106403 (a number of 23 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 28710599 and 28710608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28710641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 93367 + ... + 93673.

Almost surely, 228710640 is an apocalyptic number.

28710640 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 28710640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38497536).

28710640 is an abundant number, since it is smaller than the sum of its proper divisors (48284432).

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

28710640 is a wasteful number, since it uses less digits than its factorization.

28710640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 494 (or 488 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 28.

The square root of 28710640 is about 5358.2310513825. The cubic root of 28710640 is about 306.2064194546.

The spelling of 28710640 in words is "twenty-eight million, seven hundred ten thousand, six hundred forty".

Divisors: 1 2 4 5 7 8 10 14 16 20 28 35 40 56 70 80 112 140 167 280 307 334 560 614 668 835 1169 1228 1336 1535 1670 2149 2338 2456 2672 3070 3340 4298 4676 4912 5845 6140 6680 8596 9352 10745 11690 12280 13360 17192 18704 21490 23380 24560 34384 42980 46760 51269 85960 93520 102538 171920 205076 256345 358883 410152 512690 717766 820304 1025380 1435532 1794415 2050760 2871064 3588830 4101520 5742128 7177660 14355320 28710640