81364237924 has 6 divisors (see below), whose sum is σ = 142387416374. Its totient is φ = 40682118960.

The previous prime is 81364237891. The next prime is 81364237961. The reversal of 81364237924 is 42973246318.

It can be written as a sum of positive squares in only one way, i.e., 41364237924 + 40000000000 = 203382^2 + 200000^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10170529737 + ... + 10170529744.

Almost surely, 2^81364237924 is an apocalyptic number.

It is an amenable number.

81364237924 is a deficient number, since it is larger than the sum of its proper divisors (61023178450).

81364237924 is a wasteful number, since it uses less digits than its factorization.

81364237924 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20341059485 (or 20341059483 counting only the distinct ones).

The product of its digits is 1741824, while the sum is 49.

The spelling of 81364237924 in words is "eighty-one billion, three hundred sixty-four million, two hundred thirty-seven thousand, nine hundred twenty-four".