81252864 has 240 divisors, whose sum is σ = 293641920. Its totient is φ = 21012480.

The previous prime is 81252841. The next prime is 81252893. The reversal of 81252864 is 46825218.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 354702 + ... + 354930.

It is an arithmetic number, because the mean of its divisors is an integer number (1223508).

Almost surely, 2^81252864 is an apocalyptic number.

81252864 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81252864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (146820960).

81252864 is an abundant number, since it is smaller than the sum of its proper divisors (212389056).

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

81252864 is a wasteful number, since it uses less digits than its factorization.

81252864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 271 (or 252 counting only the distinct ones).

The product of its digits is 30720, while the sum is 36.

The square root of 81252864 is about 9014.0370533962. The cubic root of 81252864 is about 433.1246416543.

The spelling of 81252864 in words is "eighty-one million, two hundred fifty-two thousand, eight hundred sixty-four".