81393634592 has 12 divisors (see below), whose sum is σ = 160243718166. Its totient is φ = 40696817280.

The previous prime is 81393634583. The next prime is 81393634639. The reversal of 81393634592 is 29543639318.

It can be written as a sum of positive squares in only one way, i.e., 81359575696 + 34058896 = 285236^2 + 5836^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1271775509 + ... + 1271775572.

Almost surely, 2^81393634592 is an apocalyptic number.

It is an amenable number.

81393634592 is a deficient number, since it is larger than the sum of its proper divisors (78850083574).

81393634592 is a wasteful number, since it uses less digits than its factorization.

81393634592 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2543551091 (or 2543551083 counting only the distinct ones).

The product of its digits is 4199040, while the sum is 53.

The spelling of 81393634592 in words is "eighty-one billion, three hundred ninety-three million, six hundred thirty-four thousand, five hundred ninety-two".