399746 has 4 divisors (see below), whose sum is σ = 599622. Its totient is φ = 199872.

The previous prime is 399739. The next prime is 399757. The reversal of 399746 is 647993.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 647993 = 31 ⋅20903.

It can be written as a sum of positive squares in only one way, i.e., 207025 + 192721 = 455^2 + 439^2 .

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 as a sum of consecutive naturals, namely, 99935 + ... + 99938.

2³⁹⁹⁷⁴⁶ is an apocalyptic number.

399746 is a deficient number, since it is larger than the sum of its proper divisors (199876).

399746 is a wasteful number, since it uses less digits than its factorization.

399746 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 199875.

The product of its digits is 40824, while the sum is 38.

The square root of 399746 is about 632.2546955144. The cubic root of 399746 is about 73.6650309372.

The spelling of 399746 in words is "three hundred ninety-nine thousand, seven hundred forty-six".