81786874 has 12 divisors (see below), whose sum is σ = 132843726. Its totient is φ = 37747632.

The previous prime is 81786863. The next prime is 81786973. The reversal of 81786874 is 47868718.

It can be written as a sum of positive squares in 3 ways, for example, as 42185025 + 39601849 = 6495^2 + 6293^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 120649 + ... + 121324.

Almost surely, 2^81786874 is an apocalyptic number.

81786874 is a deficient number, since it is larger than the sum of its proper divisors (51056852).

81786874 is a wasteful number, since it uses less digits than its factorization.

81786874 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 242001 (or 241988 counting only the distinct ones).

The product of its digits is 602112, while the sum is 49.

The square root of 81786874 is about 9043.6095669815. The cubic root of 81786874 is about 434.0714309717.

The spelling of 81786874 in words is "eighty-one million, seven hundred eighty-six thousand, eight hundred seventy-four".