81392400 has 180 divisors, whose sum is σ = 295034688. Its totient is φ = 20739840.

The previous prime is 81392387. The next prime is 81392401. The reversal of 81392400 is 429318.

It is a tau number, because it is divible by the number of its divisors (180).

It is not an unprimeable number, because it can be changed into a prime (81392401) 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 35 ways as a sum of consecutive naturals, for example, 82309 + ... + 83291.

Almost surely, 2^81392400 is an apocalyptic number.

81392400 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 81392400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (147517344).

81392400 is an abundant number, since it is smaller than the sum of its proper divisors (213642288).

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

81392400 is a wasteful number, since it uses less digits than its factorization.

81392400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1030 (or 1016 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 81392400 is about 9021.7736615368. The cubic root of 81392400 is about 433.3724356562.

The spelling of 81392400 in words is "eighty-one million, three hundred ninety-two thousand, four hundred".