21655405226656 has 72 divisors (see below), whose sum is σ = 46547667491220. Its totient is φ = 9904105322496.

The previous prime is 21655405226647. The next prime is 21655405226671. The reversal of 21655405226656 is 65662250455612.

It can be written as a sum of positive squares in 2 ways, for example, as 21182858970256 + 472546256400 = 4602484^2 + 687420^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21655405226597 and 21655405226606.

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, 31985721 + ... + 32655736.

Almost surely, 2^{21655405226656} is an apocalyptic number.

It is an amenable number.

21655405226656 is an abundant number, since it is smaller than the sum of its proper divisors (24892262264564).

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

21655405226656 is a wasteful number, since it uses less digits than its factorization.

21655405226656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64641534 (or 64641507 counting only the distinct ones).

The product of its (nonzero) digits is 25920000, while the sum is 55.

The spelling of 21655405226656 in words is "twenty-one trillion, six hundred fifty-five billion, four hundred five million, two hundred twenty-six thousand, six hundred fifty-six".