81993300 has 36 divisors (see below), whose sum is σ = 237234816. Its totient is φ = 21864800.

The previous prime is 81993299. The next prime is 81993311. The reversal of 81993300 is 339918.

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 11 ways as a sum of consecutive naturals, for example, 136356 + ... + 136955.

It is an arithmetic number, because the mean of its divisors is an integer number (6589856).

Almost surely, 2^81993300 is an apocalyptic number.

It is an amenable number.

81993300 is an abundant number, since it is smaller than the sum of its proper divisors (155241516).

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

81993300 is a wasteful number, since it uses less digits than its factorization.

81993300 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 273328 (or 273321 counting only the distinct ones).

The product of its (nonzero) digits is 5832, while the sum is 33.

The square root of 81993300 is about 9055.0151849679. The cubic root of 81993300 is about 434.4363157237.

The spelling of 81993300 in words is "eighty-one million, nine hundred ninety-three thousand, three hundred".