81564982 has 8 divisors (see below), whose sum is σ = 123430536. Its totient is φ = 40421472.

The previous prime is 81564943. The next prime is 81565007. The reversal of 81564982 is 28946518.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 180228 + ... + 180679.

It is an arithmetic number, because the mean of its divisors is an integer number (15428817).

Almost surely, 2^81564982 is an apocalyptic number.

81564982 is a deficient number, since it is larger than the sum of its proper divisors (41865554).

81564982 is a wasteful number, since it uses less digits than its factorization.

81564982 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 361022.

The product of its digits is 138240, while the sum is 43.

The square root of 81564982 is about 9031.3333456362. Note that the first 4 decimals coincide. The cubic root of 81564982 is about 433.6785227169.

The spelling of 81564982 in words is "eighty-one million, five hundred sixty-four thousand, nine hundred eighty-two".