81866800 has 30 divisors (see below), whose sum is σ = 196685948. Its totient is φ = 32746560.

The previous prime is 81866789. The next prime is 81866857. The reversal of 81866800 is 866818.

It is a self number, because there is not a number n which added to its sum of digits gives 81866800.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 101934 + ... + 102733.

Almost surely, 2^81866800 is an apocalyptic number.

81866800 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81866800 is an abundant number, since it is smaller than the sum of its proper divisors (114819148).

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

81866800 is a wasteful number, since it uses less digits than its factorization.

81866800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204685 (or 204674 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 37.

The square root of 81866800 is about 9048.0274093307. The cubic root of 81866800 is about 434.2127833111.

The spelling of 81866800 in words is "eighty-one million, eight hundred sixty-six thousand, eight hundred".