399365 has 4 divisors (see below), whose sum is σ = 479244. Its totient is φ = 319488.

The previous prime is 399353. The next prime is 399379. The reversal of 399365 is 563993.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 563993 = 89 ⋅6337.

It can be written as a sum of positive squares in 2 ways, for example, as 83521 + 315844 = 289^2 + 562^2 .

It is a cyclic number.

It is not a de Polignac number, because 399365 - 2¹⁰ = 398341 is a prime.

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 399365.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39932 + ... + 39941.

It is an arithmetic number, because the mean of its divisors is an integer number (119811).

2³⁹⁹³⁶⁵ is an apocalyptic number.

It is an amenable number.

399365 is a deficient number, since it is larger than the sum of its proper divisors (79879).

399365 is an equidigital number, since it uses as much as digits as its factorization.

399365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79878.

The product of its digits is 21870, while the sum is 35.

The square root of 399365 is about 631.9533210610. The cubic root of 399365 is about 73.6416199894.

The spelling of 399365 in words is "three hundred ninety-nine thousand, three hundred sixty-five".