21373922761636 has 81 divisors (see below), whose sum is σ = 39954398014209. Its totient is φ = 10003408278336.

The previous prime is 21373922761613. The next prime is 21373922761657. The reversal of 21373922761636 is 63616722937312.

The square root of 21373922761636 is 4623194.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 4104246499236 + 17269676262400 = 2025894^2 + 4155680^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 15635641425 + ... + 15635642791.

Almost surely, 2^{21373922761636} is an apocalyptic number.

21373922761636 is the 4623194-th square number.

It is an amenable number.

21373922761636 is a deficient number, since it is larger than the sum of its proper divisors (18580475252573).

21373922761636 is an frugal number, since it uses more digits than its factorization.

21373922761636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2954 (or 1477 counting only the distinct ones).

The product of its digits is 20575296, while the sum is 58.

The spelling of 21373922761636 in words is "twenty-one trillion, three hundred seventy-three billion, nine hundred twenty-two million, seven hundred sixty-one thousand, six hundred thirty-six".