81718317580 has 48 divisors (see below), whose sum is σ = 177555913920. Its totient is φ = 31554860288.

The previous prime is 81718317547. The next prime is 81718317599. The reversal of 81718317580 is 8571381718.

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, 6845577 + ... + 6857503.

It is an arithmetic number, because the mean of its divisors is an integer number (3699081540).

Almost surely, 2^81718317580 is an apocalyptic number.

It is an amenable number.

81718317580 is an abundant number, since it is smaller than the sum of its proper divisors (95837596340).

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

81718317580 is a wasteful number, since it uses less digits than its factorization.

81718317580 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23778 (or 23776 counting only the distinct ones).

The product of its (nonzero) digits is 376320, while the sum is 49.

The spelling of 81718317580 in words is "eighty-one billion, seven hundred eighteen million, three hundred seventeen thousand, five hundred eighty".