639391450986 has 12 divisors (see below), whose sum is σ = 1385348143842. Its totient is φ = 213130483656.

The previous prime is 639391450981. The next prime is 639391451003. The reversal of 639391450986 is 689054193936.

639391450986 is a `hidden beast` number, since 6 + 3 + 9 + 3 + 91 + 450 + 98 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 606421970361 + 32969480625 = 778731^2 + 181575^2 .

It is not an unprimeable number, because it can be changed into a prime (639391450981) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 17760873621 + ... + 17760873656.

Almost surely, 2^639391450986 is an apocalyptic number.

639391450986 is an abundant number, since it is smaller than the sum of its proper divisors (745956692856).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

639391450986 is a wasteful number, since it uses less digits than its factorization.

639391450986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35521747285 (or 35521747282 counting only the distinct ones).

The product of its (nonzero) digits is 37791360, while the sum is 63.

The spelling of 639391450986 in words is "six hundred thirty-nine billion, three hundred ninety-one million, four hundred fifty thousand, nine hundred eighty-six".