21055422656 has 56 divisors (see below), whose sum is σ = 42969484800. Its totient is φ = 10230941952.

The previous prime is 21055422629. The next prime is 21055422671. The reversal of 21055422656 is 65622455012.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 528425 + ... + 566871.

Almost surely, 2^21055422656 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21055422656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21484742400).

21055422656 is an abundant number, since it is smaller than the sum of its proper divisors (21914062144).

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

21055422656 is a wasteful number, since it uses less digits than its factorization.

21055422656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38701 (or 38691 counting only the distinct ones).

The product of its (nonzero) digits is 144000, while the sum is 38.

Adding to 21055422656 its reverse (65622455012), we get a palindrome (86677877668).

The spelling of 21055422656 in words is "twenty-one billion, fifty-five million, four hundred twenty-two thousand, six hundred fifty-six".