21656156260 has 24 divisors (see below), whose sum is σ = 45510494400. Its totient is φ = 8656259424.

The previous prime is 21656156251. The next prime is 21656156267. The reversal of 21656156260 is 6265165612.

It is not an unprimeable number, because it can be changed into a prime (21656156267) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 359014 + ... + 414973.

It is an arithmetic number, because the mean of its divisors is an integer number (1896270600).

Almost surely, 2^21656156260 is an apocalyptic number.

21656156260 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21656156260 is an abundant number, since it is smaller than the sum of its proper divisors (23854338140).

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

21656156260 is a wasteful number, since it uses less digits than its factorization.

21656156260 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 775395 (or 775393 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 40.

The spelling of 21656156260 in words is "twenty-one billion, six hundred fifty-six million, one hundred fifty-six thousand, two hundred sixty".