399657 has 8 divisors (see below), whose sum is σ = 538560. Its totient is φ = 263600.

The previous prime is 399647. The next prime is 399667. The reversal of 399657 is 756993.

It is an interprime number because it is at equal distance from previous prime (399647) and next prime (399667).

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

It is a cyclic number.

It is not a de Polignac number, because 399657 - 2⁸ = 399401 is a prime.

It is not an unprimeable number, because it can be changed into a prime (399617) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 357 + ... + 962.

It is an arithmetic number, because the mean of its divisors is an integer number (67320).

2³⁹⁹⁶⁵⁷ is an apocalyptic number.

It is an amenable number.

399657 is a deficient number, since it is larger than the sum of its proper divisors (138903).

399657 is a wasteful number, since it uses less digits than its factorization.

399657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1423.

The product of its digits is 51030, while the sum is 39.

The square root of 399657 is about 632.1843085683. The cubic root of 399657 is about 73.6595635701.

The spelling of 399657 in words is "three hundred ninety-nine thousand, six hundred fifty-seven".