81708970 has 72 divisors (see below), whose sum is σ = 182059596. Its totient is φ = 26320896.

The previous prime is 81708967. The next prime is 81709009. The reversal of 81708970 is 7980718.

It can be written as a sum of positive squares in 6 ways, for example, as 78163281 + 3545689 = 8841^2 + 1883^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 141322 + ... + 141898.

Almost surely, 2^81708970 is an apocalyptic number.

81708970 is an abundant number, since it is smaller than the sum of its proper divisors (100350626).

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

81708970 is a wasteful number, since it uses less digits than its factorization.

81708970 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 632 (or 608 counting only the distinct ones).

The product of its (nonzero) digits is 28224, while the sum is 40.

The square root of 81708970 is about 9039.3014110605. The cubic root of 81708970 is about 433.9335659672.

The spelling of 81708970 in words is "eighty-one million, seven hundred eight thousand, nine hundred seventy".