312809 has 4 divisors (see below), whose sum is σ = 357504. Its totient is φ = 268116.

The previous prime is 312799. The next prime is 312839. The reversal of 312809 is 908213.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 312809 - 2⁸ = 312553 is a prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 312809.

It is not an unprimeable number, because it can be changed into a prime (312839) 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, 22337 + ... + 22350.

It is an arithmetic number, because the mean of its divisors is an integer number (89376).

2³¹²⁸⁰⁹ is an apocalyptic number.

It is an amenable number.

312809 is a deficient number, since it is larger than the sum of its proper divisors (44695).

312809 is an equidigital number, since it uses as much as digits as its factorization.

312809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44694.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 312809 is about 559.2933040901. The cubic root of 312809 is about 67.8827998480.

The spelling of 312809 in words is "three hundred twelve thousand, eight hundred nine".