639616725 has 72 divisors (see below), whose sum is σ = 1261383552. Its totient is φ = 307238400.

The previous prime is 639616723. The next prime is 639616759. The reversal of 639616725 is 527616936.

639616725 is a `hidden beast` number, since 6 + 3 + 9 + 616 + 7 + 25 = 666.

It is not a de Polignac number, because 639616725 - 2¹ = 639616723 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639616723) 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 in 71 ways as a sum of consecutive naturals, for example, 278532 + ... + 280818.

It is an arithmetic number, because the mean of its divisors is an integer number (17519216).

Almost surely, 2^639616725 is an apocalyptic number.

It is an amenable number.

639616725 is a deficient number, since it is larger than the sum of its proper divisors (621766827).

639616725 is a wasteful number, since it uses less digits than its factorization.

639616725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2427 (or 2419 counting only the distinct ones).

The product of its digits is 408240, while the sum is 45.

The square root of 639616725 is about 25290.6450095683. The cubic root of 639616725 is about 861.6018122946.

The spelling of 639616725 in words is "six hundred thirty-nine million, six hundred sixteen thousand, seven hundred twenty-five".