639018340 has 12 divisors (see below), whose sum is σ = 1341938556. Its totient is φ = 255607328.

The previous prime is 639018323. The next prime is 639018343. The reversal of 639018340 is 43810936.

It can be written as a sum of positive squares in 2 ways, for example, as 122456356 + 516561984 = 11066^2 + 22728^2 .

It is a junction number, because it is equal to n+sod(n) for n = 639018296 and 639018305.

It is not an unprimeable number, because it can be changed into a prime (639018343) 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 3 ways as a sum of consecutive naturals, for example, 15975439 + ... + 15975478.

It is an arithmetic number, because the mean of its divisors is an integer number (111828213).

Almost surely, 2^639018340 is an apocalyptic number.

It is an amenable number.

639018340 is an abundant number, since it is smaller than the sum of its proper divisors (702920216).

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

639018340 is a wasteful number, since it uses less digits than its factorization.

639018340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31950926 (or 31950924 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 34.

The square root of 639018340 is about 25278.8120765197. The cubic root of 639018340 is about 861.3330417210. Note that the first 3 decimals are identical.

The spelling of 639018340 in words is "six hundred thirty-nine million, eighteen thousand, three hundred forty".