21637381375 has 8 divisors (see below), whose sum is σ = 27003452112. Its totient is φ = 17309905000.

The previous prime is 21637381361. The next prime is 21637381411. The reversal of 21637381375 is 57318373612.

It is not a de Polignac number, because 21637381375 - 2⁷ = 21637381247 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 (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 86549401 + ... + 86549650.

It is an arithmetic number, because the mean of its divisors is an integer number (3375431514).

Almost surely, 2^21637381375 is an apocalyptic number.

21637381375 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21637381375 is a deficient number, since it is larger than the sum of its proper divisors (5366070737).

21637381375 is an equidigital number, since it uses as much as digits as its factorization.

21637381375 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173099066 (or 173099056 counting only the distinct ones).

The product of its digits is 635040, while the sum is 46.

The spelling of 21637381375 in words is "twenty-one billion, six hundred thirty-seven million, three hundred eighty-one thousand, three hundred seventy-five".