399309 has 4 divisors (see below), whose sum is σ = 532416. Its totient is φ = 266204.

The previous prime is 399283. The next prime is 399353. The reversal of 399309 is 903993.

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 an emirpimes, since its reverse is a distinct semiprime: 903993 = 3 ⋅301331.

It is a cyclic number.

It is not a de Polignac number, because 399309 - 2⁵ = 399277 is a prime.

It is a D-number.

It is a self number, because there is not a number n which added to its sum of digits gives 399309.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399379) 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, 66549 + ... + 66554.

It is an arithmetic number, because the mean of its divisors is an integer number (133104).

2³⁹⁹³⁰⁹ is an apocalyptic number.

It is an amenable number.

399309 is a deficient number, since it is larger than the sum of its proper divisors (133107).

399309 is a wasteful number, since it uses less digits than its factorization.

399309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133106.

The product of its (nonzero) digits is 6561, while the sum is 33.

The square root of 399309 is about 631.9090124377. The cubic root of 399309 is about 73.6381777553.

The spelling of 399309 in words is "three hundred ninety-nine thousand, three hundred nine".