639306740 has 24 divisors (see below), whose sum is σ = 1388840040. Its totient is φ = 246904448.

The previous prime is 639306721. The next prime is 639306749. The reversal of 639306740 is 47603936.

It is a happy number.

639306740 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 156450064 + 482856676 = 12508^2 + 21974^2 .

It is a junction number, because it is equal to n+sod(n) for n = 639306694 and 639306703.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639306749) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 550547 + ... + 551706.

It is an arithmetic number, because the mean of its divisors is an integer number (57868335).

Almost surely, 2^639306740 is an apocalyptic number.

It is an amenable number.

639306740 is an abundant number, since it is smaller than the sum of its proper divisors (749533300).

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

639306740 is a wasteful number, since it uses less digits than its factorization.

639306740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1102291 (or 1102289 counting only the distinct ones).

The product of its (nonzero) digits is 81648, while the sum is 38.

The square root of 639306740 is about 25284.5158150201. The cubic root of 639306740 is about 861.4626003856.

It can be divided in two parts, 639306 and 740, that added together give a palindrome (640046).

The spelling of 639306740 in words is "six hundred thirty-nine million, three hundred six thousand, seven hundred forty".