6399781136 has 40 divisors (see below), whose sum is σ = 14227464384. Its totient is φ = 2731824000.

The previous prime is 6399781127. The next prime is 6399781187. The reversal of 6399781136 is 6311879936.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 85715 + ... + 141938.

Almost surely, 2^6399781136 is an apocalyptic number.

It is an amenable number.

6399781136 is an abundant number, since it is smaller than the sum of its proper divisors (7827683248).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6399781136 is a wasteful number, since it uses less digits than its factorization.

6399781136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227919 (or 227913 counting only the distinct ones).

The product of its digits is 1469664, while the sum is 53.

The square root of 6399781136 is about 79998.6320883051. The cubic root of 6399781136 is about 1856.6143691060.

The spelling of 6399781136 in words is "six billion, three hundred ninety-nine million, seven hundred eighty-one thousand, one hundred thirty-six".