81631197375 has 128 divisors (see below), whose sum is σ = 172947640320. Its totient is φ = 33258355200.

The previous prime is 81631197367. The next prime is 81631197407. The reversal of 81631197375 is 57379113618.

It is not a de Polignac number, because 81631197375 - 2³ = 81631197367 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 948382 + ... + 1030868.

It is an arithmetic number, because the mean of its divisors is an integer number (1351153440).

Almost surely, 2^81631197375 is an apocalyptic number.

81631197375 is an abundant number, since it is smaller than the sum of its proper divisors (91316442945).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81631197375 is a wasteful number, since it uses less digits than its factorization.

81631197375 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82554 (or 82544 counting only the distinct ones).

The product of its digits is 952560, while the sum is 51.

The spelling of 81631197375 in words is "eighty-one billion, six hundred thirty-one million, one hundred ninety-seven thousand, three hundred seventy-five".