81398400 has 192 divisors, whose sum is σ = 274461600. Its totient is φ = 21196800.

The previous prime is 81398399. The next prime is 81398417. The reversal of 81398400 is 489318.

It is a tau number, because it is divible by the number of its divisors (192).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 585531 + ... + 585669.

Almost surely, 2^81398400 is an apocalyptic number.

81398400 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81398400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (137230800).

81398400 is an abundant number, since it is smaller than the sum of its proper divisors (193063200).

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

81398400 is a wasteful number, since it uses less digits than its factorization.

81398400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227 (or 210 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 33.

The square root of 81398400 is about 9022.1061842565. The cubic root of 81398400 is about 433.3830843602.

The spelling of 81398400 in words is "eighty-one million, three hundred ninety-eight thousand, four hundred".