81972160 has 28 divisors (see below), whose sum is σ = 195196968. Its totient is φ = 32788736.

The previous prime is 81972151. The next prime is 81972167. The reversal of 81972160 is 6127918.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81972167) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 127762 + ... + 128401.

Almost surely, 2^81972160 is an apocalyptic number.

81972160 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81972160 is an abundant number, since it is smaller than the sum of its proper divisors (113224808).

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

81972160 is a wasteful number, since it uses less digits than its factorization.

81972160 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 256180 (or 256170 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 34.

The square root of 81972160 is about 9053.8478007972. The cubic root of 81972160 is about 434.3989761967.

The spelling of 81972160 in words is "eighty-one million, nine hundred seventy-two thousand, one hundred sixty".