81355508 has 24 divisors (see below), whose sum is σ = 159992448. Its totient is φ = 35915616.

The previous prime is 81355493. The next prime is 81355541. The reversal of 81355508 is 80555318.

It is a congruent number.

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, 32816 + ... + 35207.

It is an arithmetic number, because the mean of its divisors is an integer number (6666352).

Almost surely, 2^81355508 is an apocalyptic number.

It is an amenable number.

81355508 is a deficient number, since it is larger than the sum of its proper divisors (78636940).

81355508 is a wasteful number, since it uses less digits than its factorization.

81355508 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68063 (or 68061 counting only the distinct ones).

The product of its (nonzero) digits is 24000, while the sum is 35.

The square root of 81355508 is about 9019.7288207573. The cubic root of 81355508 is about 433.3069488209.

The spelling of 81355508 in words is "eighty-one million, three hundred fifty-five thousand, five hundred eight".