81517388 has 12 divisors (see below), whose sum is σ = 142997232. Its totient is φ = 40661040.

The previous prime is 81517369. The next prime is 81517417. The reversal of 81517388 is 88371518.

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, 22520 + ... + 25887.

It is an arithmetic number, because the mean of its divisors is an integer number (11916436).

Almost surely, 2^81517388 is an apocalyptic number.

It is an amenable number.

81517388 is a deficient number, since it is larger than the sum of its proper divisors (61479844).

81517388 is a wasteful number, since it uses less digits than its factorization.

81517388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48832 (or 48830 counting only the distinct ones).

The product of its digits is 53760, while the sum is 41.

The square root of 81517388 is about 9028.6980235248. The cubic root of 81517388 is about 433.5941543558.

The spelling of 81517388 in words is "eighty-one million, five hundred seventeen thousand, three hundred eighty-eight".