391887 has 6 divisors (see below), whose sum is σ = 566072. Its totient is φ = 261252.

The previous prime is 391879. The next prime is 391889. The reversal of 391887 is 788193.

It is not a de Polignac number, because 391887 - 2³ = 391879 is a prime.

It is a Duffinian number.

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 391887.

It is not an unprimeable number, because it can be changed into a prime (391889) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 21763 + ... + 21780.

2³⁹¹⁸⁸⁷ is an apocalyptic number.

391887 is a deficient number, since it is larger than the sum of its proper divisors (174185).

391887 is a wasteful number, since it uses less digits than its factorization.

391887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43549 (or 43546 counting only the distinct ones).

The product of its digits is 12096, while the sum is 36.

The square root of 391887 is about 626.0087858808. The cubic root of 391887 is about 73.1790811854.

It can be divided in two parts, 3918 and 87, that added together give a triangular number (4005 = T₈₉).

The spelling of 391887 in words is "three hundred ninety-one thousand, eight hundred eighty-seven".