21660100656645 has 64 divisors (see below), whose sum is σ = 38901443781888. Its totient is φ = 10201701120000.

The previous prime is 21660100656613. The next prime is 21660100656659. The reversal of 21660100656645 is 54665600106612.

It is not a de Polignac number, because 21660100656645 - 2⁵ = 21660100656613 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21660100656594 and 21660100656603.

It is a congruent number.

It is an unprimeable number.

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 63 ways as a sum of consecutive naturals, for example, 11378416 + ... + 13144905.

It is an arithmetic number, because the mean of its divisors is an integer number (607835059092).

Almost surely, 2^{21660100656645} is an apocalyptic number.

It is an amenable number.

21660100656645 is a deficient number, since it is larger than the sum of its proper divisors (17241343125243).

21660100656645 is a wasteful number, since it uses less digits than its factorization.

21660100656645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24523494.

The product of its (nonzero) digits is 1555200, while the sum is 48.

The spelling of 21660100656645 in words is "twenty-one trillion, six hundred sixty billion, one hundred million, six hundred fifty-six thousand, six hundred forty-five".