81993200 has 30 divisors (see below), whose sum is σ = 196989624. Its totient is φ = 32797120.

The previous prime is 81993199. The next prime is 81993203. The reversal of 81993200 is 239918.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81993203) 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, 102092 + ... + 102891.

Almost surely, 2^81993200 is an apocalyptic number.

81993200 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81993200 is an abundant number, since it is smaller than the sum of its proper divisors (114996424).

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

81993200 is a wasteful number, since it uses less digits than its factorization.

81993200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205001 (or 204990 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 32.

The square root of 81993200 is about 9055.0096631644. The cubic root of 81993200 is about 434.4361391091.

The spelling of 81993200 in words is "eighty-one million, nine hundred ninety-three thousand, two hundred".