21464605665 has 32 divisors (see below), whose sum is σ = 38167209600. Its totient is φ = 11445416640.

The previous prime is 21464605571. The next prime is 21464605709. The reversal of 21464605665 is 56650646412.

21464605665 is a `hidden beast` number, since 2 + 1 + 46 + 46 + 0 + 566 + 5 = 666.

It is not a de Polignac number, because 21464605665 - 2¹⁰ = 21464604641 is a prime.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21464605665.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 778770 + ... + 805860.

It is an arithmetic number, because the mean of its divisors is an integer number (1192725300).

Almost surely, 2^21464605665 is an apocalyptic number.

It is an amenable number.

21464605665 is a deficient number, since it is larger than the sum of its proper divisors (16702603935).

21464605665 is a wasteful number, since it uses less digits than its factorization.

21464605665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32974 (or 32968 counting only the distinct ones).

The product of its (nonzero) digits is 1036800, while the sum is 45.

The spelling of 21464605665 in words is "twenty-one billion, four hundred sixty-four million, six hundred five thousand, six hundred sixty-five".