21265164563504 has 20 divisors (see below), whose sum is σ = 42314803811664. Its totient is φ = 10345215192768.

The previous prime is 21265164563501. The next prime is 21265164563543. The reversal of 21265164563504 is 40536546156212.

It is not an unprimeable number, because it can be changed into a prime (21265164563501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17960442452 + ... + 17960443635.

Almost surely, 2^{21265164563504} is an apocalyptic number.

It is an amenable number.

21265164563504 is a deficient number, since it is larger than the sum of its proper divisors (21049639248160).

21265164563504 is a wasteful number, since it uses less digits than its factorization.

21265164563504 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35920886132 (or 35920886126 counting only the distinct ones).

The product of its (nonzero) digits is 5184000, while the sum is 50.

The spelling of 21265164563504 in words is "twenty-one trillion, two hundred sixty-five billion, one hundred sixty-four million, five hundred sixty-three thousand, five hundred four".