81616172 has 48 divisors (see below), whose sum is σ = 165110400. Its totient is φ = 34911360.

The previous prime is 81616163. The next prime is 81616177. The reversal of 81616172 is 27161618.

It is a happy number.

It is a super-2 number, since 2×81616172² = 13322399063867168, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81616177) 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, 194579 + ... + 194997.

It is an arithmetic number, because the mean of its divisors is an integer number (3439800).

Almost surely, 2^81616172 is an apocalyptic number.

It is an amenable number.

81616172 is an abundant number, since it is smaller than the sum of its proper divisors (83494228).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81616172 is a wasteful number, since it uses less digits than its factorization.

81616172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 686 (or 684 counting only the distinct ones).

The product of its digits is 4032, while the sum is 32.

The square root of 81616172 is about 9034.1669234080. The cubic root of 81616172 is about 433.7692289670.

The spelling of 81616172 in words is "eighty-one million, six hundred sixteen thousand, one hundred seventy-two".