81194720 has 48 divisors (see below), whose sum is σ = 203113008. Its totient is φ = 30566400.

The previous prime is 81194653. The next prime is 81194749. The reversal of 81194720 is 2749118.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12206 + ... + 17645.

It is an arithmetic number, because the mean of its divisors is an integer number (4231521).

Almost surely, 2^81194720 is an apocalyptic number.

81194720 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81194720 is an abundant number, since it is smaller than the sum of its proper divisors (121918288).

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

81194720 is a wasteful number, since it uses less digits than its factorization.

81194720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29883 (or 29875 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 32.

The square root of 81194720 is about 9010.8112842296. The cubic root of 81194720 is about 433.0213033128.

The spelling of 81194720 in words is "eighty-one million, one hundred ninety-four thousand, seven hundred twenty".