639396775 has 12 divisors (see below), whose sum is σ = 839490912. Its totient is φ = 481427840.

The previous prime is 639396773. The next prime is 639396817. The reversal of 639396775 is 577693936.

It is not a de Polignac number, because 639396775 - 2¹ = 639396773 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639396773) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 751807 + ... + 752656.

It is an arithmetic number, because the mean of its divisors is an integer number (69957576).

Almost surely, 2^639396775 is an apocalyptic number.

639396775 is a deficient number, since it is larger than the sum of its proper divisors (200094137).

639396775 is a wasteful number, since it uses less digits than its factorization.

639396775 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1504490 (or 1504485 counting only the distinct ones).

The product of its digits is 6429780, while the sum is 55.

The square root of 639396775 is about 25286.2961898337. The cubic root of 639396775 is about 861.5030390564.

The spelling of 639396775 in words is "six hundred thirty-nine million, three hundred ninety-six thousand, seven hundred seventy-five".