81557488 has 20 divisors (see below), whose sum is σ = 160610008. Its totient is φ = 40109760.

The previous prime is 81557479. The next prime is 81557537. The reversal of 81557488 is 88475518.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40806 + ... + 42757.

Almost surely, 2^81557488 is an apocalyptic number.

It is an amenable number.

81557488 is a deficient number, since it is larger than the sum of its proper divisors (79052520).

81557488 is a wasteful number, since it uses less digits than its factorization.

81557488 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83632 (or 83626 counting only the distinct ones).

The product of its digits is 358400, while the sum is 46.

The square root of 81557488 is about 9030.9184472013. The cubic root of 81557488 is about 433.6652405203.

The spelling of 81557488 in words is "eighty-one million, five hundred fifty-seven thousand, four hundred eighty-eight".