21262561056 has 72 divisors (see below), whose sum is σ = 65962273104. Its totient is φ = 6443199360.

The previous prime is 21262561049. The next prime is 21262561087. The reversal of 21262561056 is 65016526212.

21262561056 is a `hidden beast` number, since 2 + 12 + 6 + 25 + 610 + 5 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21262561056.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3352666 + ... + 3359001.

It is an arithmetic number, because the mean of its divisors is an integer number (916142682).

Almost surely, 2^21262561056 is an apocalyptic number.

It is an amenable number.

21262561056 is an abundant number, since it is smaller than the sum of its proper divisors (44699712048).

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

21262561056 is a wasteful number, since it uses less digits than its factorization.

21262561056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6711694 (or 6711683 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The spelling of 21262561056 in words is "twenty-one billion, two hundred sixty-two million, five hundred sixty-one thousand, fifty-six".