391863 has 4 divisors (see below), whose sum is σ = 522488. Its totient is φ = 261240.

The previous prime is 391861. The next prime is 391873. The reversal of 391863 is 368193.

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

It is not a de Polignac number, because 391863 - 2¹ = 391861 is a prime.

It is a super-2 number, since 2×391863² = 307113221538, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 391863.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 391863.

It is not an unprimeable number, because it can be changed into a prime (391861) 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, 65308 + ... + 65313.

It is an arithmetic number, because the mean of its divisors is an integer number (130622).

2³⁹¹⁸⁶³ is an apocalyptic number.

391863 is a deficient number, since it is larger than the sum of its proper divisors (130625).

391863 is a wasteful number, since it uses less digits than its factorization.

391863 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130624.

The product of its digits is 3888, while the sum is 30.

The square root of 391863 is about 625.9896165273. The cubic root of 391863 is about 73.1775872737.

The spelling of 391863 in words is "three hundred ninety-one thousand, eight hundred sixty-three".