21572731828 has 12 divisors (see below), whose sum is σ = 38464588260. Its totient is φ = 10582849472.

The previous prime is 21572731811. The next prime is 21572731861. The reversal of 21572731828 is 82813727512.

It can be written as a sum of positive squares in 2 ways, for example, as 6498294544 + 15074437284 = 80612^2 + 122778^2 .

It is a super-3 number, since 3×21572731828³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 50878873 + ... + 50879296.

It is an arithmetic number, because the mean of its divisors is an integer number (3205382355).

Almost surely, 2^21572731828 is an apocalyptic number.

It is an amenable number.

21572731828 is a deficient number, since it is larger than the sum of its proper divisors (16891856432).

21572731828 is a wasteful number, since it uses less digits than its factorization.

21572731828 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101758226 (or 101758224 counting only the distinct ones).

The product of its digits is 376320, while the sum is 46.

The spelling of 21572731828 in words is "twenty-one billion, five hundred seventy-two million, seven hundred thirty-one thousand, eight hundred twenty-eight".