81988600 has 24 divisors (see below), whose sum is σ = 190623960. Its totient is φ = 32795360.

The previous prime is 81988579. The next prime is 81988607. The reversal of 81988600 is 688918.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81988607) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 204772 + ... + 205171.

It is an arithmetic number, because the mean of its divisors is an integer number (7942665).

Almost surely, 2^81988600 is an apocalyptic number.

It is an amenable number.

81988600 is an abundant number, since it is smaller than the sum of its proper divisors (108635360).

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

81988600 is a wasteful number, since it uses less digits than its factorization.

81988600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 409959 (or 409950 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 40.

The square root of 81988600 is about 9054.7556565597. The cubic root of 81988600 is about 434.4280146808.

The spelling of 81988600 in words is "eighty-one million, nine hundred eighty-eight thousand, six hundred".