21621271264564 has 12 divisors (see below), whose sum is σ = 37838213388388. Its totient is φ = 10810353153600.

The previous prime is 21621271264511. The next prime is 21621271264591. The reversal of 21621271264564 is 46546217212612.

It can be written as a sum of positive squares in 2 ways, for example, as 20957095163664 + 664176100900 = 4577892^2 + 814970^2 .

It is a super-3 number, since 3×21621271264564³ (a number of 41 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 70447407 + ... + 70753654.

Almost surely, 2^{21621271264564} is an apocalyptic number.

It is an amenable number.

21621271264564 is a deficient number, since it is larger than the sum of its proper divisors (16216942123824).

21621271264564 is a wasteful number, since it uses less digits than its factorization.

21621271264564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141239346 (or 141239344 counting only the distinct ones).

The product of its digits is 1935360, while the sum is 49.

The spelling of 21621271264564 in words is "twenty-one trillion, six hundred twenty-one billion, two hundred seventy-one million, two hundred sixty-four thousand, five hundred sixty-four".