81172516 has 12 divisors (see below), whose sum is σ = 142475788. Its totient is φ = 40465152.

The previous prime is 81172493. The next prime is 81172523. The reversal of 81172516 is 61527118.

It can be written as a sum of positive squares in 2 ways, for example, as 6522916 + 74649600 = 2554^2 + 8640^2 .

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28761 + ... + 31456.

Almost surely, 2^81172516 is an apocalyptic number.

It is an amenable number.

81172516 is a deficient number, since it is larger than the sum of its proper divisors (61303272).

81172516 is a wasteful number, since it uses less digits than its factorization.

81172516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60558 (or 60556 counting only the distinct ones).

The product of its digits is 3360, while the sum is 31.

The square root of 81172516 is about 9009.5791244652. The cubic root of 81172516 is about 432.9818275046.

The spelling of 81172516 in words is "eighty-one million, one hundred seventy-two thousand, five hundred sixteen".