21660100656644 has 6 divisors (see below), whose sum is σ = 37905176149134. Its totient is φ = 10830050328320.

The previous prime is 21660100656613. The next prime is 21660100656659. The reversal of 21660100656644 is 44665600106612.

It can be written as a sum of positive squares in only one way, i.e., 16309724560900 + 5350376095744 = 4038530^2 + 2313088^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2707512582077 + ... + 2707512582084.

It is an arithmetic number, because the mean of its divisors is an integer number (6317529358189).

Almost surely, 2^{21660100656644} is an apocalyptic number.

It is an amenable number.

21660100656644 is a deficient number, since it is larger than the sum of its proper divisors (16245075492490).

21660100656644 is a wasteful number, since it uses less digits than its factorization.

21660100656644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5415025164165 (or 5415025164163 counting only the distinct ones).

The product of its (nonzero) digits is 1244160, while the sum is 47.

The spelling of 21660100656644 in words is "twenty-one trillion, six hundred sixty billion, one hundred million, six hundred fifty-six thousand, six hundred forty-four".