81264816 has 80 divisors (see below), whose sum is σ = 234394720. Its totient is φ = 26956800.

The previous prime is 81264809. The next prime is 81264853. The reversal of 81264816 is 61846218.

81264816 is a `hidden beast` number, since 8 + 1 + 2 + 648 + 1 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 134916 + ... + 135516.

It is an arithmetic number, because the mean of its divisors is an integer number (2929934).

Almost surely, 2^81264816 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 81264816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (117197360).

81264816 is an abundant number, since it is smaller than the sum of its proper divisors (153129904).

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

81264816 is a wasteful number, since it uses less digits than its factorization.

81264816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 931 (or 919 counting only the distinct ones).

The product of its digits is 18432, while the sum is 36.

The square root of 81264816 is about 9014.6999950082. The cubic root of 81264816 is about 433.1458776316.

The spelling of 81264816 in words is "eighty-one million, two hundred sixty-four thousand, eight hundred sixteen".