81658400 has 72 divisors (see below), whose sum is σ = 201487104. Its totient is φ = 32313600.

The previous prime is 81658397. The next prime is 81658417. The reversal of 81658400 is 485618.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 81905 + ... + 82895.

It is an arithmetic number, because the mean of its divisors is an integer number (2798432).

Almost surely, 2^81658400 is an apocalyptic number.

81658400 is a gapful number since it is divisible by the number (80) 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 81658400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (100743552).

81658400 is an abundant number, since it is smaller than the sum of its proper divisors (119828704).

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

81658400 is a wasteful number, since it uses less digits than its factorization.

81658400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1114 (or 1101 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 32.

The square root of 81658400 is about 9036.5037486851. The cubic root of 81658400 is about 433.8440264341.

The spelling of 81658400 in words is "eighty-one million, six hundred fifty-eight thousand, four hundred".