81659967 has 16 divisors (see below), whose sum is σ = 117279360. Its totient is φ = 50373792.

The previous prime is 81659947. The next prime is 81659971. The reversal of 81659967 is 76995618.

It is a de Polignac number, because none of the positive numbers 2^k-81659967 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81659927) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14208 + ... + 19109.

It is an arithmetic number, because the mean of its divisors is an integer number (7329960).

Almost surely, 2^81659967 is an apocalyptic number.

81659967 is a deficient number, since it is larger than the sum of its proper divisors (35619393).

81659967 is a wasteful number, since it uses less digits than its factorization.

81659967 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33382.

The product of its digits is 816480, while the sum is 51.

The square root of 81659967 is about 9036.5904521562. The cubic root of 81659967 is about 433.8468015282.

The spelling of 81659967 in words is "eighty-one million, six hundred fifty-nine thousand, nine hundred sixty-seven".