815131 has 4 divisors (see below), whose sum is σ = 818064. Its totient is φ = 812200.

The previous prime is 815123. The next prime is 815141. The reversal of 815131 is 131518.

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

It is a cyclic number.

It is not a de Polignac number, because 815131 - 2³ = 815123 is a prime.

It is a super-2 number, since 2×815131² = 1328877094322, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 7.

It is a zygodrome in base 7.

It is a junction number, because it is equal to n+sod(n) for n = 815099 and 815108.

It is not an unprimeable number, because it can be changed into a prime (815141) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1000 + ... + 1621.

It is an arithmetic number, because the mean of its divisors is an integer number (204516).

2⁸¹⁵¹³¹ is an apocalyptic number.

815131 is a deficient number, since it is larger than the sum of its proper divisors (2933).

815131 is a wasteful number, since it uses less digits than its factorization.

815131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2932.

The product of its digits is 120, while the sum is 19.

The square root of 815131 is about 902.8460555377. The cubic root of 815131 is about 93.4133907775.

Adding to 815131 its reverse (131518), we get a palindrome (946649).

It can be divided in two parts, 815 and 131, that added together give a triangular number (946 = T₄₃).

The spelling of 815131 in words is "eight hundred fifteen thousand, one hundred thirty-one".