309431 has 4 divisors (see below), whose sum is σ = 317832. Its totient is φ = 301032.

The previous prime is 309403. The next prime is 309433. The reversal of 309431 is 134903.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 134903 = 313 ⋅431.

It is not a de Polignac number, because 309431 - 2⁶ = 309367 is a prime.

It is a super-2 number, since 2×309431² = 191495087522, which contains 22 as substring.

It is a Duffinian number.

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 309431.

It is not an unprimeable number, because it can be changed into a prime (309433) 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 in 3 ways as a sum of consecutive naturals, for example, 4145 + ... + 4218.

It is an arithmetic number, because the mean of its divisors is an integer number (79458).

2³⁰⁹⁴³¹ is an apocalyptic number.

309431 is a deficient number, since it is larger than the sum of its proper divisors (8401).

309431 is an equidigital number, since it uses as much as digits as its factorization.

309431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8400.

The product of its (nonzero) digits is 324, while the sum is 20.

The square root of 309431 is about 556.2652245108. The cubic root of 309431 is about 67.6375612597.

It can be divided in two parts, 3094 and 31, that added together give a 5-th power (3125 = 5⁵).

The spelling of 309431 in words is "three hundred nine thousand, four hundred thirty-one".