21667504601664 has 112 divisors (see below), whose sum is σ = 65753239933440. Its totient is φ = 6989517596160.

The previous prime is 21667504601663. The next prime is 21667504601737. The reversal of 21667504601664 is 46610640576612.

21667504601664 is a `hidden beast` number, since 2 + 1 + 6 + 6 + 7 + 504 + 60 + 16 + 64 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 21667504601664.

It is not an unprimeable number, because it can be changed into a prime (21667504601663) 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 15 ways as a sum of consecutive naturals, for example, 202189419 + ... + 202296554.

Almost surely, 2^{21667504601664} is an apocalyptic number.

21667504601664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21667504601664 is an abundant number, since it is smaller than the sum of its proper divisors (44085735331776).

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

21667504601664 is a wasteful number, since it uses less digits than its factorization.

21667504601664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 404486025 (or 404486009 counting only the distinct ones).

The product of its (nonzero) digits is 8709120, while the sum is 54.

The spelling of 21667504601664 in words is "twenty-one trillion, six hundred sixty-seven billion, five hundred four million, six hundred one thousand, six hundred sixty-four".