639946858 has 8 divisors (see below), whose sum is σ = 965224260. Its totient is φ = 318205440.

The previous prime is 639946711. The next prime is 639946859. The reversal of 639946858 is 858649936.

It can be written as a sum of positive squares in 2 ways, for example, as 639938209 + 8649 = 25297^2 + 93^2 .

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

It is not an unprimeable number, because it can be changed into a prime (639946859) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 883543 + ... + 884266.

Almost surely, 2^639946858 is an apocalyptic number.

639946858 is a deficient number, since it is larger than the sum of its proper divisors (325277402).

639946858 is a wasteful number, since it uses less digits than its factorization.

639946858 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1767992.

The product of its digits is 11197440, while the sum is 58.

The square root of 639946858 is about 25297.1709485468. The cubic root of 639946858 is about 861.7500230675.

The spelling of 639946858 in words is "six hundred thirty-nine million, nine hundred forty-six thousand, eight hundred fifty-eight".