639563957 has 4 divisors (see below), whose sum is σ = 643137120. Its totient is φ = 635990796.

The previous prime is 639563933. The next prime is 639563963. The reversal of 639563957 is 759365936.

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 639563957 - 2⁶ = 639563893 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 639563899 and 639563908.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639563257) 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 3 ways as a sum of consecutive naturals, for example, 1786313 + ... + 1786670.

It is an arithmetic number, because the mean of its divisors is an integer number (160784280).

Almost surely, 2^639563957 is an apocalyptic number.

It is an amenable number.

639563957 is a deficient number, since it is larger than the sum of its proper divisors (3573163).

639563957 is a wasteful number, since it uses less digits than its factorization.

639563957 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3573162.

The product of its digits is 4592700, while the sum is 53.

The square root of 639563957 is about 25289.6017564532. The cubic root of 639563957 is about 861.5781177637.

The spelling of 639563957 in words is "six hundred thirty-nine million, five hundred sixty-three thousand, nine hundred fifty-seven".