81353997508 has 48 divisors (see below), whose sum is σ = 164445159424. Its totient is φ = 34494400800.

The previous prime is 81353997457. The next prime is 81353997541. The reversal of 81353997508 is 80579935318.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3121933 + ... + 3147883.

Almost surely, 2^81353997508 is an apocalyptic number.

It is an amenable number.

81353997508 is an abundant number, since it is smaller than the sum of its proper divisors (83091161916).

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

81353997508 is a wasteful number, since it uses less digits than its factorization.

81353997508 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27152 (or 27150 counting only the distinct ones).

The product of its (nonzero) digits is 8164800, while the sum is 58.

The spelling of 81353997508 in words is "eighty-one billion, three hundred fifty-three million, nine hundred ninety-seven thousand, five hundred eight".