639424937 has 2 divisors, whose sum is σ = 639424938. Its totient is φ = 639424936.

The previous prime is 639424901. The next prime is 639424939. The reversal of 639424937 is 739424936.

It is a happy number.

639424937 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 476505241 + 162919696 = 21829^2 + 12764^2 .

It is a cyclic number.

It is not a de Polignac number, because 639424937 - 2¹² = 639420841 is a prime.

Together with 639424939, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 639424891 and 639424900.

It is not a weakly prime, because it can be changed into another prime (639424939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319712468 + 319712469.

It is an arithmetic number, because the mean of its divisors is an integer number (319712469).

Almost surely, 2^639424937 is an apocalyptic number.

It is an amenable number.

639424937 is a deficient number, since it is larger than the sum of its proper divisors (1).

639424937 is an equidigital number, since it uses as much as digits as its factorization.

639424937 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 979776, while the sum is 47.

The square root of 639424937 is about 25286.8530465932. The cubic root of 639424937 is about 861.5156870674.

Subtracting 639424937 from its reverse (739424936), we obtain a palindrome (99999999).

The spelling of 639424937 in words is "six hundred thirty-nine million, four hundred twenty-four thousand, nine hundred thirty-seven".