815231 has 2 divisors, whose sum is σ = 815232. Its totient is φ = 815230.

The previous prime is 815209. The next prime is 815251. The reversal of 815231 is 132518.

It is an a-pointer prime, because the next prime (815251) can be obtained adding 815231 to its sum of digits (20).

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-815231 is a prime.

It is a super-2 number, since 2×815231² = 1329203166722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a zygodrome in base 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (815251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 407615 + 407616.

It is an arithmetic number, because the mean of its divisors is an integer number (407616).

2⁸¹⁵²³¹ is an apocalyptic number.

815231 is a deficient number, since it is larger than the sum of its proper divisors (1).

815231 is an equidigital number, since it uses as much as digits as its factorization.

815231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 240, while the sum is 20.

The square root of 815231 is about 902.9014342662. The cubic root of 815231 is about 93.4172105959.

Adding to 815231 its reverse (132518), we get a palindrome (947749).

The spelling of 815231 in words is "eight hundred fifteen thousand, two hundred thirty-one".