131173821 has 6 divisors (see below), whose sum is σ = 189473310. Its totient is φ = 87449208.

The previous prime is 131173813. The next prime is 131173831. The reversal of 131173821 is 128371131.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 87216921 + 43956900 = 9339^2 + 6630^2 .

It is not a de Polignac number, because 131173821 - 2³ = 131173813 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131173811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7287426 + ... + 7287443.

It is an arithmetic number, because the mean of its divisors is an integer number (31578885).

Almost surely, 2^131173821 is an apocalyptic number.

It is an amenable number.

131173821 is a deficient number, since it is larger than the sum of its proper divisors (58299489).

131173821 is a wasteful number, since it uses less digits than its factorization.

131173821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14574875 (or 14574872 counting only the distinct ones).

The product of its digits is 1008, while the sum is 27.

The square root of 131173821 is about 11453.1140306905. The cubic root of 131173821 is about 508.0998380354.

The spelling of 131173821 in words is "one hundred thirty-one million, one hundred seventy-three thousand, eight hundred twenty-one".