399005 has 4 divisors (see below), whose sum is σ = 478812. Its totient is φ = 319200.

The previous prime is 398989. The next prime is 399023. The reversal of 399005 is 500993.

399005 = T₃₉₇ + T₃₉₈ + ... + T₄₀₁.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 109561 + 289444 = 331^2 + 538^2 .

It is not a de Polignac number, because 399005 - 2⁴ = 398989 is a prime.

It is a Duffinian number.

It is a congruent number.

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, 39896 + ... + 39905.

It is an arithmetic number, because the mean of its divisors is an integer number (119703).

2³⁹⁹⁰⁰⁵ is an apocalyptic number.

It is an amenable number.

399005 is a deficient number, since it is larger than the sum of its proper divisors (79807).

399005 is an equidigital number, since it uses as much as digits as its factorization.

399005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79806.

The product of its (nonzero) digits is 1215, while the sum is 26.

The square root of 399005 is about 631.6684256792. The cubic root of 399005 is about 73.6194857236.

Adding to 399005 its reverse (500993), we get a palindrome (899998).

The spelling of 399005 in words is "three hundred ninety-nine thousand, five".