309213 has 24 divisors (see below), whose sum is σ = 494208. Its totient is φ = 185472.

The previous prime is 309193. The next prime is 309223. The reversal of 309213 is 312903.

It is not a de Polignac number, because 309213 - 2⁹ = 308701 is a prime.

It is a super-2 number, since 2×309213² = 191225358738, which contains 22 as substring.

It is a nialpdrome in base 13.

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 309213.

It is not an unprimeable number, because it can be changed into a prime (309223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6556 + ... + 6602.

It is an arithmetic number, because the mean of its divisors is an integer number (20592).

2³⁰⁹²¹³ is an apocalyptic number.

It is an amenable number.

309213 is a deficient number, since it is larger than the sum of its proper divisors (184995).

309213 is a wasteful number, since it uses less digits than its factorization.

309213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113 (or 110 counting only the distinct ones).

The product of its (nonzero) digits is 162, while the sum is 18.

The square root of 309213 is about 556.0692402930. The cubic root of 309213 is about 67.6216735471.

The spelling of 309213 in words is "three hundred nine thousand, two hundred thirteen".