812315809 has 2 divisors, whose sum is σ = 812315810. Its totient is φ = 812315808.

The previous prime is 812315761. The next prime is 812315813. The reversal of 812315809 is 908513218.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 728190225 + 84125584 = 26985^2 + 9172^2 .

It is a cyclic number.

It is not a de Polignac number, because 812315809 - 2⁷ = 812315681 is a prime.

It is not a weakly prime, because it can be changed into another prime (812315849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 406157904 + 406157905.

It is an arithmetic number, because the mean of its divisors is an integer number (406157905).

Almost surely, 2^812315809 is an apocalyptic number.

It is an amenable number.

812315809 is a deficient number, since it is larger than the sum of its proper divisors (1).

812315809 is an equidigital number, since it uses as much as digits as its factorization.

812315809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17280, while the sum is 37.

The square root of 812315809 is about 28501.1545204751. The cubic root of 812315809 is about 933.0572715715.

It can be divided in two parts, 8123 and 15809, that added together give a palindrome (23932).

The spelling of 812315809 in words is "eight hundred twelve million, three hundred fifteen thousand, eight hundred nine".