639129228 has 24 divisors (see below), whose sum is σ = 1502034240. Its totient is φ = 211509840.

The previous prime is 639129223. The next prime is 639129233. The reversal of 639129228 is 822921936.

It is an interprime number because it is at equal distance from previous prime (639129223) and next prime (639129233).

It is a self number, because there is not a number n which added to its sum of digits gives 639129228.

It is not an unprimeable number, because it can be changed into a prime (639129223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 189918 + ... + 193253.

It is an arithmetic number, because the mean of its divisors is an integer number (62584760).

Almost surely, 2^639129228 is an apocalyptic number.

It is an amenable number.

639129228 is an abundant number, since it is smaller than the sum of its proper divisors (862905012).

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

639129228 is a wasteful number, since it uses less digits than its factorization.

639129228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 383317 (or 383315 counting only the distinct ones).

The product of its digits is 93312, while the sum is 42.

The square root of 639129228 is about 25281.0052806450. The cubic root of 639129228 is about 861.3828608306.

The spelling of 639129228 in words is "six hundred thirty-nine million, one hundred twenty-nine thousand, two hundred twenty-eight".