639425549 has 12 divisors (see below), whose sum is σ = 757859004. Its totient is φ = 537735744.

The previous prime is 639425531. The next prime is 639425581. The reversal of 639425549 is 945524936.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 231587524 + 407838025 = 15218^2 + 20195^2 .

It is not a de Polignac number, because 639425549 - 2²⁸ = 370990093 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639425249) 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, 120512 + ... + 125705.

It is an arithmetic number, because the mean of its divisors is an integer number (63154917).

Almost surely, 2^639425549 is an apocalyptic number.

It is an amenable number.

639425549 is a deficient number, since it is larger than the sum of its proper divisors (118433455).

639425549 is a wasteful number, since it uses less digits than its factorization.

639425549 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 246284 (or 246277 counting only the distinct ones).

The product of its digits is 1166400, while the sum is 47.

The square root of 639425549 is about 25286.8651477402. The cubic root of 639425549 is about 861.5159619224.

The spelling of 639425549 in words is "six hundred thirty-nine million, four hundred twenty-five thousand, five hundred forty-nine".