815291 has 2 divisors, whose sum is σ = 815292. Its totient is φ = 815290.

The previous prime is 815279. The next prime is 815317. The reversal of 815291 is 192518.

It is a happy number.

It is an a-pointer prime, because the next prime (815317) can be obtained adding 815291 to its sum of digits (26).

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-815291 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 815291.

It is not a weakly prime, because it can be changed into another prime (815231) by changing a digit.

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 as a sum of consecutive naturals, namely, 407645 + 407646.

It is an arithmetic number, because the mean of its divisors is an integer number (407646).

2⁸¹⁵²⁹¹ is an apocalyptic number.

815291 is a deficient number, since it is larger than the sum of its proper divisors (1).

815291 is an equidigital number, since it uses as much as digits as its factorization.

815291 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 720, while the sum is 26.

The square root of 815291 is about 902.9346598730. The cubic root of 815291 is about 93.4195023370.

The spelling of 815291 in words is "eight hundred fifteen thousand, two hundred ninety-one".