81716931 has 10 divisors (see below), whose sum is σ = 122071092. Its totient is φ = 54477900.

The previous prime is 81716923. The next prime is 81716951. The reversal of 81716931 is 13961718.

It is not a de Polignac number, because 81716931 - 2³ = 81716923 is a prime.

It is a super-2 number, since 2×81716931² = 13355313624117522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81716911) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 504345 + ... + 504506.

Almost surely, 2^81716931 is an apocalyptic number.

81716931 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

81716931 is a deficient number, since it is larger than the sum of its proper divisors (40354161).

81716931 is a wasteful number, since it uses less digits than its factorization.

81716931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1008863 (or 1008854 counting only the distinct ones).

The product of its digits is 9072, while the sum is 36.

The square root of 81716931 is about 9039.7417551609. The cubic root of 81716931 is about 433.9476583936.

The spelling of 81716931 in words is "eighty-one million, seven hundred sixteen thousand, nine hundred thirty-one".