6399731 has 8 divisors (see below), whose sum is σ = 7060704. Its totient is φ = 5762880.

The previous prime is 6399719. The next prime is 6399737. The reversal of 6399731 is 1379936.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6399731 - 2¹⁸ = 6137587 is a prime.

It is a super-2 number, since 2×6399731² = 81913113744722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6399737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5471 + ... + 6536.

It is an arithmetic number, because the mean of its divisors is an integer number (882588).

Almost surely, 2^6399731 is an apocalyptic number.

6399731 is a deficient number, since it is larger than the sum of its proper divisors (660973).

6399731 is a wasteful number, since it uses less digits than its factorization.

6399731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12061.

The product of its digits is 30618, while the sum is 38.

The square root of 6399731 is about 2529.7689617829. The cubic root of 6399731 is about 185.6609520843.

The spelling of 6399731 in words is "six million, three hundred ninety-nine thousand, seven hundred thirty-one".