81616512 has 64 divisors (see below), whose sum is σ = 226244160. Its totient is φ = 26019840.

The previous prime is 81616501. The next prime is 81616543. The reversal of 81616512 is 21561618.

It is a tau number, because it is divible by the number of its divisors (64).

It is a super-2 number, since 2×81616512² = 13322510062092288, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81616512.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4212 + ... + 13452.

It is an arithmetic number, because the mean of its divisors is an integer number (3535065).

Almost surely, 2^81616512 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81616512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (113122080).

81616512 is an abundant number, since it is smaller than the sum of its proper divisors (144627648).

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

81616512 is a wasteful number, since it uses less digits than its factorization.

81616512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9281 (or 9269 counting only the distinct ones).

The product of its digits is 2880, while the sum is 30.

The square root of 81616512 is about 9034.1857408402. The cubic root of 81616512 is about 433.7698313041.

It can be divided in two parts, 81616 and 512, that added together give a palindrome (82128).

The spelling of 81616512 in words is "eighty-one million, six hundred sixteen thousand, five hundred twelve".