309913 has 4 divisors (see below), whose sum is σ = 311040. Its totient is φ = 308788.

The previous prime is 309899. The next prime is 309929. The reversal of 309913 is 319903.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-309913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (309013) 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, 156 + ... + 802.

It is an arithmetic number, because the mean of its divisors is an integer number (77760).

2³⁰⁹⁹¹³ is an apocalyptic number.

It is an amenable number.

309913 is a deficient number, since it is larger than the sum of its proper divisors (1127).

309913 is an equidigital number, since it uses as much as digits as its factorization.

309913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1126.

The product of its (nonzero) digits is 729, while the sum is 25.

The square root of 309913 is about 556.6983024943. The cubic root of 309913 is about 67.6726626679.

The spelling of 309913 in words is "three hundred nine thousand, nine hundred thirteen".