21510164665 has 16 divisors (see below), whose sum is σ = 28181986560. Its totient is φ = 15630853120.

The previous prime is 21510164593. The next prime is 21510164747. The reversal of 21510164665 is 56646101512.

It is not a de Polignac number, because 21510164665 - 2¹⁵ = 21510131897 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 93745 + ... + 227614.

It is an arithmetic number, because the mean of its divisors is an integer number (1761374160).

Almost surely, 2^21510164665 is an apocalyptic number.

It is an amenable number.

21510164665 is a deficient number, since it is larger than the sum of its proper divisors (6671821895).

21510164665 is a wasteful number, since it uses less digits than its factorization.

21510164665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322592.

The product of its (nonzero) digits is 43200, while the sum is 37.

The spelling of 21510164665 in words is "twenty-one billion, five hundred ten million, one hundred sixty-four thousand, six hundred sixty-five".