639134869 has 2 divisors, whose sum is σ = 639134870. Its totient is φ = 639134868.

The previous prime is 639134827. The next prime is 639134921. The reversal of 639134869 is 968431936.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 629759025 + 9375844 = 25095^2 + 3062^2 .

It is a cyclic number.

It is not a de Polignac number, because 639134869 - 2¹¹ = 639132821 is a prime.

It is a super-2 number, since 2×639134869² = 816986761543294322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639134809) 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 as a sum of consecutive naturals, namely, 319567434 + 319567435.

It is an arithmetic number, because the mean of its divisors is an integer number (319567435).

Almost surely, 2^639134869 is an apocalyptic number.

It is an amenable number.

639134869 is a deficient number, since it is larger than the sum of its proper divisors (1).

639134869 is an equidigital number, since it uses as much as digits as its factorization.

639134869 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 839808, while the sum is 49.

The square root of 639134869 is about 25281.1168463737. The cubic root of 639134869 is about 861.3853950320.

The spelling of 639134869 in words is "six hundred thirty-nine million, one hundred thirty-four thousand, eight hundred sixty-nine".