639846957 has 8 divisors (see below), whose sum is σ = 876186976. Its totient is φ = 415035792.

The previous prime is 639846953. The next prime is 639846967. The reversal of 639846957 is 759648936.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 639846957 - 2² = 639846953 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 639846897 and 639846906.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639846953) 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 7 ways as a sum of consecutive naturals, for example, 2882083 + ... + 2882304.

It is an arithmetic number, because the mean of its divisors is an integer number (109523372).

Almost surely, 2^639846957 is an apocalyptic number.

It is an amenable number.

639846957 is a deficient number, since it is larger than the sum of its proper divisors (236340019).

639846957 is a wasteful number, since it uses less digits than its factorization.

639846957 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5764427.

The product of its digits is 9797760, while the sum is 57.

The square root of 639846957 is about 25295.1963226222. The cubic root of 639846957 is about 861.7051786307.

The spelling of 639846957 in words is "six hundred thirty-nine million, eight hundred forty-six thousand, nine hundred fifty-seven".