81693800 has 24 divisors (see below), whose sum is σ = 189938550. Its totient is φ = 32677440.

The previous prime is 81693737. The next prime is 81693803. The reversal of 81693800 is 839618.

It can be written as a sum of positive squares in 3 ways, for example, as 46812964 + 34880836 = 6842^2 + 5906^2 .

It is not an unprimeable number, because it can be changed into a prime (81693803) by changing a digit.

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, 204035 + ... + 204434.

Almost surely, 2^81693800 is an apocalyptic number.

It is an amenable number.

81693800 is an abundant number, since it is smaller than the sum of its proper divisors (108244750).

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

81693800 is a wasteful number, since it uses less digits than its factorization.

81693800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 408485 (or 408476 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 35.

The square root of 81693800 is about 9038.4622585924. The cubic root of 81693800 is about 433.9067097578.

The spelling of 81693800 in words is "eighty-one million, six hundred ninety-three thousand, eight hundred".