840399 has 12 divisors (see below), whose sum is σ = 1303704. Its totient is φ = 480144.

The previous prime is 840353. The next prime is 840439. The reversal of 840399 is 993048.

It is not a de Polignac number, because 840399 - 2⁹ = 839887 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (840319) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2712 + ... + 3005.

It is an arithmetic number, because the mean of its divisors is an integer number (108642).

2⁸⁴⁰³⁹⁹ is an apocalyptic number.

840399 is a deficient number, since it is larger than the sum of its proper divisors (463305).

840399 is a wasteful number, since it uses less digits than its factorization.

840399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5734 (or 5727 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 33.

The square root of 840399 is about 916.7327854942. The cubic root of 840399 is about 94.3688166058.

It can be divided in two parts, 84039 and 9, that added together give a palindrome (84048).

The spelling of 840399 in words is "eight hundred forty thousand, three hundred ninety-nine".