81942400 has 96 divisors (see below), whose sum is σ = 209640600. Its totient is φ = 31610880.

The previous prime is 81942379. The next prime is 81942437. The reversal of 81942400 is 424918.

It is a super-3 number, since 3×81942400³ (a number of 25 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 92359 + ... + 93241.

Almost surely, 2^81942400 is an apocalyptic number.

81942400 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 81942400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (104820300).

81942400 is an abundant number, since it is smaller than the sum of its proper divisors (127698200).

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

81942400 is a wasteful number, since it uses less digits than its factorization.

81942400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 936 (or 919 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 81942400 is about 9052.2041514760. The cubic root of 81942400 is about 434.3464003046.

The spelling of 81942400 in words is "eighty-one million, nine hundred forty-two thousand, four hundred".