6399 has 10 divisors (see below), whose sum is σ = 9680.
Its totient is φ = 4212.
The previous prime is 6397. The next prime is 6421. The reversal of 6399 is 9936.
It is a Cunningham number, because it is equal to 802-1.
It is not a de Polignac number, because 6399 - 21 = 6397 is a prime.
It is a Harshad number since it is a multiple of its sum of digits (27).
It is a Duffinian number.
6399 is a modest number, since divided by 99 gives 63 as remainder.
6399 is a lucky number.
It is a plaindrome in base 16.
It is a nialpdrome in base 3 and base 9.
It is a zygodrome in base 2.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (6397) by changing a digit.
It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 42 + ... + 120.
It is an arithmetic number, because the mean of its divisors is an integer number (968).
26399 is an apocalyptic number.
6399 is a deficient number, since it is larger than the sum of its proper divisors (3281).
6399 is an equidigital number, since it uses as much as digits as its factorization.
6399 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 91 (or 82 counting only the distinct ones).
The product of its digits is 1458, while the sum is 27.
The square root of 6399 is about 79.9937497558.
The cubic root of 6399 is about 18.5653882864.
The spelling of 6399 in words is "six thousand, three hundred ninety-nine".