639128311 has 4 divisors (see below), whose sum is σ = 676724112. Its totient is φ = 601532512.

The previous prime is 639128309. The next prime is 639128323. The reversal of 639128311 is 113821936.

639128311 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 639128311 - 2¹ = 639128309 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639128341) 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, 18797875 + ... + 18797908.

It is an arithmetic number, because the mean of its divisors is an integer number (169181028).

Almost surely, 2^639128311 is an apocalyptic number.

639128311 is a deficient number, since it is larger than the sum of its proper divisors (37595801).

639128311 is a wasteful number, since it uses less digits than its factorization.

639128311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37595800.

The product of its digits is 7776, while the sum is 34.

The square root of 639128311 is about 25280.9871444926. The cubic root of 639128311 is about 861.3824488699.

The spelling of 639128311 in words is "six hundred thirty-nine million, one hundred twenty-eight thousand, three hundred eleven".