81599923975 has 6 divisors (see below), whose sum is σ = 101183905760. Its totient is φ = 65279939160.

The previous prime is 81599923969. The next prime is 81599923997. The reversal of 81599923975 is 57932999518.

It is not a de Polignac number, because 81599923975 - 2⁹ = 81599923463 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81599923975.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1631998455 + ... + 1631998504.

Almost surely, 2^81599923975 is an apocalyptic number.

81599923975 is a deficient number, since it is larger than the sum of its proper divisors (19583981785).

81599923975 is a wasteful number, since it uses less digits than its factorization.

81599923975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3263996969 (or 3263996964 counting only the distinct ones).

The product of its digits is 55112400, while the sum is 67.

The spelling of 81599923975 in words is "eighty-one billion, five hundred ninety-nine million, nine hundred twenty-three thousand, nine hundred seventy-five".