639607169 has 4 divisors (see below), whose sum is σ = 639962160. Its totient is φ = 639252180.

The previous prime is 639607153. The next prime is 639607181. The reversal of 639607169 is 961706936.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 639607169 - 2⁴ = 639607153 is a prime.

It is a super-2 number, since 2×639607169² = 818194661272389122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (639607139) 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, 174779 + ... + 178400.

It is an arithmetic number, because the mean of its divisors is an integer number (159990540).

Almost surely, 2^639607169 is an apocalyptic number.

It is an amenable number.

639607169 is a deficient number, since it is larger than the sum of its proper divisors (354991).

639607169 is a wasteful number, since it uses less digits than its factorization.

639607169 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 354990.

The product of its (nonzero) digits is 367416, while the sum is 47.

The square root of 639607169 is about 25290.4560852508. The cubic root of 639607169 is about 861.5975214396.

The spelling of 639607169 in words is "six hundred thirty-nine million, six hundred seven thousand, one hundred sixty-nine".