6399121 has 4 divisors (see below), whose sum is σ = 6406452. Its totient is φ = 6391792.

The previous prime is 6399119. The next prime is 6399137. The reversal of 6399121 is 1219936.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 1132096 + 5267025 = 1064^2 + 2295^2 .

It is a cyclic number.

It is not a de Polignac number, because 6399121 - 2¹ = 6399119 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6399161) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2146 + ... + 4171.

It is an arithmetic number, because the mean of its divisors is an integer number (1601613).

Almost surely, 2^6399121 is an apocalyptic number.

It is an amenable number.

6399121 is a deficient number, since it is larger than the sum of its proper divisors (7331).

6399121 is a wasteful number, since it uses less digits than its factorization.

6399121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7330.

The product of its digits is 2916, while the sum is 31.

The square root of 6399121 is about 2529.6483945402. The cubic root of 6399121 is about 185.6550530458.

The spelling of 6399121 in words is "six million, three hundred ninety-nine thousand, one hundred twenty-one".