81970380 has 60 divisors (see below), whose sum is σ = 257149200. Its totient is φ = 21858336.

The previous prime is 81970373. The next prime is 81970393. The reversal of 81970380 is 8307918.

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 23680 + ... + 26919.

It is an arithmetic number, because the mean of its divisors is an integer number (4285820).

Almost surely, 2^81970380 is an apocalyptic number.

It is an amenable number.

81970380 is an abundant number, since it is smaller than the sum of its proper divisors (175178820).

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

81970380 is a wasteful number, since it uses less digits than its factorization.

81970380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50620 (or 50609 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 36.

The square root of 81970380 is about 9053.7494995168. The cubic root of 81970380 is about 434.3958318943.

The spelling of 81970380 in words is "eighty-one million, nine hundred seventy thousand, three hundred eighty".