391284 has 24 divisors (see below), whose sum is σ = 1014720. Its totient is φ = 130392.

The previous prime is 391283. The next prime is 391291. The reversal of 391284 is 482193.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391283) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1704 + ... + 1919.

It is an arithmetic number, because the mean of its divisors is an integer number (42280).

2³⁹¹²⁸⁴ is an apocalyptic number.

It is an amenable number.

391284 is an abundant number, since it is smaller than the sum of its proper divisors (623436).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

391284 is a wasteful number, since it uses less digits than its factorization.

391284 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3636 (or 3628 counting only the distinct ones).

The product of its digits is 1728, while the sum is 27.

The square root of 391284 is about 625.5269778355. The cubic root of 391284 is about 73.1415281508.

Subtracting 391284 from its reverse (482193), we obtain a palindrome (90909).

The spelling of 391284 in words is "three hundred ninety-one thousand, two hundred eighty-four".