81015225992 has 32 divisors (see below), whose sum is σ = 153051600600. Its totient is φ = 40202294784.

The previous prime is 81015225953. The next prime is 81015226003. The reversal of 81015225992 is 29952251018.

It can be written as a sum of positive squares in 4 ways, for example, as 77325149476 + 3690076516 = 278074^2 + 60746^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 736058 + ... + 838934.

Almost surely, 2^81015225992 is an apocalyptic number.

It is an amenable number.

81015225992 is a deficient number, since it is larger than the sum of its proper divisors (72036374608).

81015225992 is a wasteful number, since it uses less digits than its factorization.

81015225992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103625 (or 103621 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 44.

The spelling of 81015225992 in words is "eighty-one billion, fifteen million, two hundred twenty-five thousand, nine hundred ninety-two".