81087800 has 24 divisors (see below), whose sum is σ = 188529600.
Its totient is φ = 32435040.
The previous prime is 81087779. The next prime is 81087817. The reversal of 81087800 is 878018.
It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.
It is a congruent number.
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 5 ways as a sum of consecutive naturals, for example, 202520 + ... + 202919.
It is an arithmetic number, because the mean of its divisors is an integer number (7855400).
Almost surely, 281087800 is an apocalyptic number.
It is an amenable number.
81087800 is an abundant number, since it is smaller than the sum of its proper divisors (107441800).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
81087800 is a wasteful number, since it uses less digits than its factorization.
81087800 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 405455 (or 405446 counting only the distinct ones).
The product of its (nonzero) digits is 3584, while the sum is 32.
The square root of 81087800 is about 9004.8764566761.
The cubic root of 81087800 is about 432.8311473718.
The spelling of 81087800 in words is "eighty-one million, eighty-seven thousand, eight hundred".