399745 has 8 divisors (see below), whose sum is σ = 495360. Its totient is φ = 309360.

The previous prime is 399739. The next prime is 399757. The reversal of 399745 is 547993.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 399745 - 2⁷ = 399617 is a prime.

It is a d-powerful number, because it can be written as 3 + 9² + 7³ + 9⁵ + 4⁹ + 5⁷ .

399745 is a lucky number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1135 + ... + 1444.

It is an arithmetic number, because the mean of its divisors is an integer number (61920).

2³⁹⁹⁷⁴⁵ is an apocalyptic number.

It is an amenable number.

399745 is a deficient number, since it is larger than the sum of its proper divisors (95615).

399745 is a wasteful number, since it uses less digits than its factorization.

399745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2615.

The product of its digits is 34020, while the sum is 37.

The square root of 399745 is about 632.2539046934. The cubic root of 399745 is about 73.6649695106.

The spelling of 399745 in words is "three hundred ninety-nine thousand, seven hundred forty-five".