399723 has 4 divisors (see below), whose sum is σ = 532968. Its totient is φ = 266480.

The previous prime is 399719. The next prime is 399727. The reversal of 399723 is 327993.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 327993 = 3 ⋅109331.

It is an interprime number because it is at equal distance from previous prime (399719) and next prime (399727).

It is a cyclic number.

It is not a de Polignac number, because 399723 - 2² = 399719 is a prime.

It is a D-number.

It is not an unprimeable number, because it can be changed into a prime (399727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66618 + ... + 66623.

It is an arithmetic number, because the mean of its divisors is an integer number (133242).

2³⁹⁹⁷²³ is an apocalyptic number.

399723 is a deficient number, since it is larger than the sum of its proper divisors (133245).

399723 is a wasteful number, since it uses less digits than its factorization.

399723 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133244.

The product of its digits is 10206, while the sum is 33.

The square root of 399723 is about 632.2365063803. The cubic root of 399723 is about 73.6636180999.

The spelling of 399723 in words is "three hundred ninety-nine thousand, seven hundred twenty-three".