81696974624 has 24 divisors (see below), whose sum is σ = 166387159260. Its totient is φ = 39439918336.

The previous prime is 81696974561. The next prime is 81696974659. The reversal of 81696974624 is 42647969618.

It can be written as a sum of positive squares in 2 ways, for example, as 73729627024 + 7967347600 = 271532^2 + 89260^2 .

It is a super-3 number, since 3×81696974624³ (a number of 34 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44016839 + ... + 44018694.

Almost surely, 2^81696974624 is an apocalyptic number.

It is an amenable number.

81696974624 is an abundant number, since it is smaller than the sum of its proper divisors (84690184636).

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

81696974624 is a wasteful number, since it uses less digits than its factorization.

81696974624 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88035572 (or 88035564 counting only the distinct ones).

The product of its digits is 31352832, while the sum is 62.

The spelling of 81696974624 in words is "eighty-one billion, six hundred ninety-six million, nine hundred seventy-four thousand, six hundred twenty-four".