21929636655 has 40 divisors (see below), whose sum is σ = 39331770192. Its totient is φ = 11689598592.

The previous prime is 21929636629. The next prime is 21929636711. The reversal of 21929636655 is 55663692912.

It is a happy number.

21929636655 is a `hidden beast` number, since 2 + 192 + 96 + 366 + 5 + 5 = 666.

It is not a de Polignac number, because 21929636655 - 2¹¹ = 21929634607 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 807579 + ... + 834291.

Almost surely, 2^21929636655 is an apocalyptic number.

21929636655 is a deficient number, since it is larger than the sum of its proper divisors (17402133537).

21929636655 is a wasteful number, since it uses less digits than its factorization.

21929636655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28757 (or 28748 counting only the distinct ones).

The product of its digits is 5248800, while the sum is 54.

The spelling of 21929636655 in words is "twenty-one billion, nine hundred twenty-nine million, six hundred thirty-six thousand, six hundred fifty-five".