81970499 has 16 divisors (see below), whose sum is σ = 89886720. Its totient is φ = 74299680.

The previous prime is 81970477. The next prime is 81970531. The reversal of 81970499 is 99407918.

It is a de Polignac number, because none of the positive numbers 2^k-81970499 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81970409) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 216092 + ... + 216470.

It is an arithmetic number, because the mean of its divisors is an integer number (5617920).

Almost surely, 2^81970499 is an apocalyptic number.

81970499 is a deficient number, since it is larger than the sum of its proper divisors (7916221).

81970499 is a wasteful number, since it uses less digits than its factorization.

81970499 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 650.

The product of its (nonzero) digits is 163296, while the sum is 47.

The square root of 81970499 is about 9053.7560713772. The cubic root of 81970499 is about 434.3960421047.

The spelling of 81970499 in words is "eighty-one million, nine hundred seventy thousand, four hundred ninety-nine".