399739 has 2 divisors, whose sum is σ = 399740. Its totient is φ = 399738.

The previous prime is 399731. The next prime is 399757. The reversal of 399739 is 937993.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 399739 - 2³ = 399731 is a prime.

It is not a weakly prime, because it can be changed into another prime (399731) 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 as a sum of consecutive naturals, namely, 199869 + 199870.

It is an arithmetic number, because the mean of its divisors is an integer number (199870).

2³⁹⁹⁷³⁹ is an apocalyptic number.

399739 is a deficient number, since it is larger than the sum of its proper divisors (1).

399739 is an equidigital number, since it uses as much as digits as its factorization.

399739 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 45927, while the sum is 40.

The square root of 399739 is about 632.2491597464. The cubic root of 399739 is about 73.6646009490.

The spelling of 399739 in words is "three hundred ninety-nine thousand, seven hundred thirty-nine".