638711228 has 48 divisors (see below), whose sum is σ = 1177128960. Its totient is φ = 302875200.

The previous prime is 638711221. The next prime is 638711251. The reversal of 638711228 is 822117836.

It is a junction number, because it is equal to n+sod(n) for n = 638711191 and 638711200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638711221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2356733 + ... + 2357003.

It is an arithmetic number, because the mean of its divisors is an integer number (24523520).

Almost surely, 2^638711228 is an apocalyptic number.

It is an amenable number.

638711228 is a deficient number, since it is larger than the sum of its proper divisors (538417732).

638711228 is a wasteful number, since it uses less digits than its factorization.

638711228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 618 (or 616 counting only the distinct ones).

The product of its digits is 32256, while the sum is 38.

The square root of 638711228 is about 25272.7368521892. The cubic root of 638711228 is about 861.1950341528.

The spelling of 638711228 in words is "six hundred thirty-eight million, seven hundred eleven thousand, two hundred twenty-eight".