21264566164 has 6 divisors (see below), whose sum is σ = 37212990794. Its totient is φ = 10632283080.

The previous prime is 21264566153. The next prime is 21264566203. The reversal of 21264566164 is 46166546212.

It can be written as a sum of positive squares in only one way, i.e., 20451860100 + 812706064 = 143010^2 + 28508^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21264566164.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2658070767 + ... + 2658070774.

Almost surely, 2^21264566164 is an apocalyptic number.

It is an amenable number.

21264566164 is a deficient number, since it is larger than the sum of its proper divisors (15948424630).

21264566164 is a wasteful number, since it uses less digits than its factorization.

21264566164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5316141545 (or 5316141543 counting only the distinct ones).

The product of its digits is 414720, while the sum is 43.

The spelling of 21264566164 in words is "twenty-one billion, two hundred sixty-four million, five hundred sixty-six thousand, one hundred sixty-four".