82515681 has 6 divisors (see below), whose sum is σ = 119189330. Its totient is φ = 55010448.

The previous prime is 82515677. The next prime is 82515683. The reversal of 82515681 is 18651528.

82515681 is a `hidden beast` number, since 82 + 515 + 68 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 81270225 + 1245456 = 9015^2 + 1116^2 .

It is not a de Polignac number, because 82515681 - 2² = 82515677 is a prime.

It is a super-2 number, since 2×82515681² = 13617675221787522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (82515683) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4584196 + ... + 4584213.

Almost surely, 2^82515681 is an apocalyptic number.

It is an amenable number.

82515681 is a deficient number, since it is larger than the sum of its proper divisors (36673649).

82515681 is a wasteful number, since it uses less digits than its factorization.

82515681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9168415 (or 9168412 counting only the distinct ones).

The product of its digits is 19200, while the sum is 36.

The square root of 82515681 is about 9083.8142319182. The cubic root of 82515681 is about 435.3569642258.

The spelling of 82515681 in words is "eighty-two million, five hundred fifteen thousand, six hundred eighty-one".