231172813 has 4 divisors (see below), whose sum is σ = 231248668. Its totient is φ = 231096960.

The previous prime is 231172771. The next prime is 231172819. The reversal of 231172813 is 318271132.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 55398249 + 175774564 = 7443^2 + 13258^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-231172813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231172819) 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 3 ways as a sum of consecutive naturals, for example, 33156 + ... + 39517.

It is an arithmetic number, because the mean of its divisors is an integer number (57812167).

Almost surely, 2^231172813 is an apocalyptic number.

It is an amenable number.

231172813 is a deficient number, since it is larger than the sum of its proper divisors (75855).

231172813 is an equidigital number, since it uses as much as digits as its factorization.

231172813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75854.

The product of its digits is 2016, while the sum is 28.

The square root of 231172813 is about 15204.3682210081. The cubic root of 231172813 is about 613.7322137196.

The spelling of 231172813 in words is "two hundred thirty-one million, one hundred seventy-two thousand, eight hundred thirteen".