81831272 has 32 divisors (see below), whose sum is σ = 163031400. Its totient is φ = 38433024.

The previous prime is 81831259. The next prime is 81831283. The reversal of 81831272 is 27213818.

It can be written as a sum of positive squares in 4 ways, for example, as 73034116 + 8797156 = 8546^2 + 2966^2 .

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 7 ways as a sum of consecutive naturals, for example, 3818 + ... + 13350.

Almost surely, 2^81831272 is an apocalyptic number.

It is an amenable number.

81831272 is a deficient number, since it is larger than the sum of its proper divisors (81200128).

81831272 is a wasteful number, since it uses less digits than its factorization.

81831272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9605 (or 9601 counting only the distinct ones).

The product of its digits is 5376, while the sum is 32.

The square root of 81831272 is about 9046.0638954188. The cubic root of 81831272 is about 434.1499619806.

The spelling of 81831272 in words is "eighty-one million, eight hundred thirty-one thousand, two hundred seventy-two".