21172892612 has 6 divisors (see below), whose sum is σ = 37052562078. Its totient is φ = 10586446304.

The previous prime is 21172892579. The next prime is 21172892623. The reversal of 21172892612 is 21629827112.

It can be written as a sum of positive squares in only one way, i.e., 12158149696 + 9014742916 = 110264^2 + 94946^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21172892612.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2646611573 + ... + 2646611580.

It is an arithmetic number, because the mean of its divisors is an integer number (6175427013).

Almost surely, 2^21172892612 is an apocalyptic number.

It is an amenable number.

21172892612 is a deficient number, since it is larger than the sum of its proper divisors (15879669466).

21172892612 is a wasteful number, since it uses less digits than its factorization.

21172892612 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5293223157 (or 5293223155 counting only the distinct ones).

The product of its digits is 48384, while the sum is 41.

The spelling of 21172892612 in words is "twenty-one billion, one hundred seventy-two million, eight hundred ninety-two thousand, six hundred twelve".