81756800 has 96 divisors (see below), whose sum is σ = 209166300. Its totient is φ = 31539200.

The previous prime is 81756799. The next prime is 81756811. The reversal of 81756800 is 865718.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 17372224 + 64384576 = 4168^2 + 8024^2 .

It is a hoax number, since the sum of its digits (35) coincides with the sum of the digits of its distinct prime factors.

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 11 ways as a sum of consecutive naturals, for example, 92360 + ... + 93240.

Almost surely, 2^81756800 is an apocalyptic number.

81756800 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 81756800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (104583150).

81756800 is an abundant number, since it is smaller than the sum of its proper divisors (127409500).

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

81756800 is a wasteful number, since it uses less digits than its factorization.

81756800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 934 (or 917 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 35.

The square root of 81756800 is about 9041.9466930523. The cubic root of 81756800 is about 434.0182200510.

The spelling of 81756800 in words is "eighty-one million, seven hundred fifty-six thousand, eight hundred".