21089639125 has 8 divisors (see below), whose sum is σ = 26319869784. Its totient is φ = 16871711200.

The previous prime is 21089639069. The next prime is 21089639147. The reversal of 21089639125 is 52193698012.

It can be written as a sum of positive squares in 4 ways, for example, as 325405521 + 20764233604 = 18039^2 + 144098^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21089639125 is a prime.

It is a Duffinian number.

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 7 ways as a sum of consecutive naturals, for example, 84358432 + ... + 84358681.

It is an arithmetic number, because the mean of its divisors is an integer number (3289983723).

Almost surely, 2^21089639125 is an apocalyptic number.

21089639125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21089639125 is a deficient number, since it is larger than the sum of its proper divisors (5230230659).

21089639125 is an equidigital number, since it uses as much as digits as its factorization.

21089639125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 168717128 (or 168717118 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 46.

The spelling of 21089639125 in words is "twenty-one billion, eighty-nine million, six hundred thirty-nine thousand, one hundred twenty-five".