639425431 has 2 divisors, whose sum is σ = 639425432. Its totient is φ = 639425430.

The previous prime is 639425419. The next prime is 639425441. The reversal of 639425431 is 134524936.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 639425431 - 2⁵ = 639425399 is a prime.

It is a super-2 number, since 2×639425431² = 817729763619071522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639425401) by changing a digit.

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 as a sum of consecutive naturals, namely, 319712715 + 319712716.

It is an arithmetic number, because the mean of its divisors is an integer number (319712716).

Almost surely, 2^639425431 is an apocalyptic number.

639425431 is a deficient number, since it is larger than the sum of its proper divisors (1).

639425431 is an equidigital number, since it uses as much as digits as its factorization.

639425431 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 77760, while the sum is 37.

The square root of 639425431 is about 25286.8628145130. The cubic root of 639425431 is about 861.5159089275.

The spelling of 639425431 in words is "six hundred thirty-nine million, four hundred twenty-five thousand, four hundred thirty-one".