6399678825 has 18 divisors (see below), whose sum is σ = 11462536254. Its totient is φ = 3413161920.

The previous prime is 6399678811. The next prime is 6399678827. The reversal of 6399678825 is 5288769936.

It can be written as a sum of positive squares in 3 ways, for example, as 1454354496 + 4945324329 = 38136^2 + 70323^2 .

It is not a de Polignac number, because 6399678825 - 2⁸ = 6399678569 is a prime.

It is a super-3 number, since 3×6399678825³ (a number of 30 digits) contains 333 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (6399678827) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 14221284 + ... + 14221733.

Almost surely, 2^6399678825 is an apocalyptic number.

It is an amenable number.

6399678825 is a deficient number, since it is larger than the sum of its proper divisors (5062857429).

6399678825 is a wasteful number, since it uses less digits than its factorization.

6399678825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28443033 (or 28443025 counting only the distinct ones).

The product of its digits is 39191040, while the sum is 63.

The square root of 6399678825 is about 79997.9926310654. The cubic root of 6399678825 is about 1856.6044753778.

The spelling of 6399678825 in words is "six billion, three hundred ninety-nine million, six hundred seventy-eight thousand, eight hundred twenty-five".