399891 has 8 divisors (see below), whose sum is σ = 564624. Its totient is φ = 250880.

The previous prime is 399887. The next prime is 399899. The reversal of 399891 is 198993.

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 399891 - 2² = 399887 is a prime.

It is not an unprimeable number, because it can be changed into a prime (399899) 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, 3870 + ... + 3971.

It is an arithmetic number, because the mean of its divisors is an integer number (70578).

2³⁹⁹⁸⁹¹ is an apocalyptic number.

399891 is a deficient number, since it is larger than the sum of its proper divisors (164733).

399891 is a wasteful number, since it uses less digits than its factorization.

399891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7861.

The product of its digits is 17496, while the sum is 39.

The square root of 399891 is about 632.3693540962. The cubic root of 399891 is about 73.6739367076.

The spelling of 399891 in words is "three hundred ninety-nine thousand, eight hundred ninety-one".