81975890331 has 48 divisors (see below), whose sum is σ = 123838097760. Its totient is φ = 52189401600.

The previous prime is 81975890327. The next prime is 81975890333. The reversal of 81975890331 is 13309857918.

It is not a de Polignac number, because 81975890331 - 2² = 81975890327 is a prime.

It is a super-2 number, since 2×81975890331² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81975890333) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 10115181 + ... + 10123281.

It is an arithmetic number, because the mean of its divisors is an integer number (2579960370).

Almost surely, 2^81975890331 is an apocalyptic number.

81975890331 is a deficient number, since it is larger than the sum of its proper divisors (41862207429).

81975890331 is a wasteful number, since it uses less digits than its factorization.

81975890331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8556 (or 8553 counting only the distinct ones).

The product of its (nonzero) digits is 1632960, while the sum is 54.

The spelling of 81975890331 in words is "eighty-one billion, nine hundred seventy-five million, eight hundred ninety thousand, three hundred thirty-one".