309443 has 4 divisors (see below), whose sum is σ = 313440. Its totient is φ = 305448.

The previous prime is 309437. The next prime is 309457. The reversal of 309443 is 344903.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-309443 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (309403) 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, 1880 + ... + 2037.

It is an arithmetic number, because the mean of its divisors is an integer number (78360).

2³⁰⁹⁴⁴³ is an apocalyptic number.

309443 is a deficient number, since it is larger than the sum of its proper divisors (3997).

309443 is an equidigital number, since it uses as much as digits as its factorization.

309443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3996.

The product of its (nonzero) digits is 1296, while the sum is 23.

The square root of 309443 is about 556.2760106278. The cubic root of 309443 is about 67.6384355960.

The spelling of 309443 in words is "three hundred nine thousand, four hundred forty-three".