639742122 has 24 divisors (see below), whose sum is σ = 1459061760. Its totient is φ = 202023720.

The previous prime is 639742121. The next prime is 639742123. The reversal of 639742122 is 221247936.

639742122 is a `hidden beast` number, since 639 + 7 + 4 + 2 + 12 + 2 = 666.

It is an interprime number because it is at equal distance from previous prime (639742121) and next prime (639742123).

It is a super-2 number, since 2×639742122² = 818539965322125768, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (639742121) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 934954 + ... + 935637.

It is an arithmetic number, because the mean of its divisors is an integer number (60794240).

Almost surely, 2^639742122 is an apocalyptic number.

639742122 is an abundant number, since it is smaller than the sum of its proper divisors (819319638).

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

639742122 is a wasteful number, since it uses less digits than its factorization.

639742122 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1870618 (or 1870615 counting only the distinct ones).

The product of its digits is 36288, while the sum is 36.

The square root of 639742122 is about 25293.1240063382. The cubic root of 639742122 is about 861.6581143572.

The spelling of 639742122 in words is "six hundred thirty-nine million, seven hundred forty-two thousand, one hundred twenty-two".