391899 has 4 divisors (see below), whose sum is σ = 522536. Its totient is φ = 261264.

The previous prime is 391891. The next prime is 391903. The reversal of 391899 is 998193.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 391899 - 2³ = 391891 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (391891) 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, 65314 + ... + 65319.

It is an arithmetic number, because the mean of its divisors is an integer number (130634).

2³⁹¹⁸⁹⁹ is an apocalyptic number.

391899 is a deficient number, since it is larger than the sum of its proper divisors (130637).

391899 is a wasteful number, since it uses less digits than its factorization.

391899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130636.

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

The square root of 391899 is about 626.0183703375. The cubic root of 391899 is about 73.1798281184.

The spelling of 391899 in words is "three hundred ninety-one thousand, eight hundred ninety-nine".