81976320500 has 48 divisors (see below), whose sum is σ = 189567849744. Its totient is φ = 30861670400.

The previous prime is 81976320463. The next prime is 81976320539. The reversal of 81976320500 is 502367918.

It can be written as a sum of positive squares in 8 ways, for example, as 28739064676 + 53237255824 = 169526^2 + 230732^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4813637 + ... + 4830636.

It is an arithmetic number, because the mean of its divisors is an integer number (3949330203).

Almost surely, 2^81976320500 is an apocalyptic number.

It is an amenable number.

81976320500 is an abundant number, since it is smaller than the sum of its proper divisors (107591529244).

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

81976320500 is a wasteful number, since it uses less digits than its factorization.

81976320500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9644309 (or 9644297 counting only the distinct ones).

The product of its (nonzero) digits is 90720, while the sum is 41.

The spelling of 81976320500 in words is "eighty-one billion, nine hundred seventy-six million, three hundred twenty thousand, five hundred".