21642551162505 has 96 divisors (see below), whose sum is σ = 46377821607936. Its totient is φ = 9091726820352.

The previous prime is 21642551162473. The next prime is 21642551162509. The reversal of 21642551162505 is 50526115524612.

It is a happy number.

21642551162505 is a `hidden beast` number, since 2 + 1 + 6 + 4 + 2 + 5 + 5 + 11 + 625 + 0 + 5 = 666.

It is not a de Polignac number, because 21642551162505 - 2⁵ = 21642551162473 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (21642551162509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 10936852 + ... + 12763221.

It is an arithmetic number, because the mean of its divisors is an integer number (483102308416).

Almost surely, 2^{21642551162505} is an apocalyptic number.

It is an amenable number.

21642551162505 is an abundant number, since it is smaller than the sum of its proper divisors (24735270445431).

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

21642551162505 is a wasteful number, since it uses less digits than its factorization.

21642551162505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23700327 (or 23700324 counting only the distinct ones).

The product of its (nonzero) digits is 720000, while the sum is 45.

The spelling of 21642551162505 in words is "twenty-one trillion, six hundred forty-two billion, five hundred fifty-one million, one hundred sixty-two thousand, five hundred five".