81715959 has 40 divisors (see below), whose sum is σ = 133432992. Its totient is φ = 49533120.

The previous prime is 81715951. The next prime is 81715961. The reversal of 81715959 is 95951718.

It is not a de Polignac number, because 81715959 - 2³ = 81715951 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81715951) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 74217 + ... + 75309.

Almost surely, 2^81715959 is an apocalyptic number.

81715959 is a deficient number, since it is larger than the sum of its proper divisors (51717033).

81715959 is a wasteful number, since it uses less digits than its factorization.

81715959 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1189 (or 1180 counting only the distinct ones).

The product of its digits is 113400, while the sum is 45.

The square root of 81715959 is about 9039.6879924033. The cubic root of 81715959 is about 433.9459378248.

The spelling of 81715959 in words is "eighty-one million, seven hundred fifteen thousand, nine hundred fifty-nine".