815491 has 2 divisors, whose sum is σ = 815492. Its totient is φ = 815490.

The previous prime is 815471. The next prime is 815501. The reversal of 815491 is 194518.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 815491 - 2⁵ = 815459 is a prime.

It is a zygodrome in base 2.

It is not a weakly prime, because it can be changed into another prime (815401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 407745 + 407746.

It is an arithmetic number, because the mean of its divisors is an integer number (407746).

2⁸¹⁵⁴⁹¹ is an apocalyptic number.

815491 is a deficient number, since it is larger than the sum of its proper divisors (1).

815491 is an equidigital number, since it uses as much as digits as its factorization.

815491 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1440, while the sum is 28.

The square root of 815491 is about 903.0454030668. The cubic root of 815491 is about 93.4271406620.

The spelling of 815491 in words is "eight hundred fifteen thousand, four hundred ninety-one".