311809 has 4 divisors (see below), whose sum is σ = 328240. Its totient is φ = 295380.

The previous prime is 311807. The next prime is 311821. The reversal of 311809 is 908113.

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 311809 - 2¹ = 311807 is a prime.

It is a Duffinian number.

311809 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 311809.

It is not an unprimeable number, because it can be changed into a prime (311803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8187 + ... + 8224.

It is an arithmetic number, because the mean of its divisors is an integer number (82060).

2³¹¹⁸⁰⁹ is an apocalyptic number.

It is an amenable number.

311809 is a deficient number, since it is larger than the sum of its proper divisors (16431).

311809 is a wasteful number, since it uses less digits than its factorization.

311809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16430.

The product of its (nonzero) digits is 216, while the sum is 22.

The square root of 311809 is about 558.3986031501. The cubic root of 311809 is about 67.8103858345.

The spelling of 311809 in words is "three hundred eleven thousand, eight hundred nine".