638307228 has 96 divisors (see below), whose sum is σ = 1707241536. Its totient is φ = 183877632.

The previous prime is 638307227. The next prime is 638307251. The reversal of 638307228 is 822703836.

It is a happy number.

638307228 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×638307228² = 814872234634087968, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638307227) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 617400 + ... + 618432.

It is an arithmetic number, because the mean of its divisors is an integer number (17783766).

Almost surely, 2^638307228 is an apocalyptic number.

638307228 is a gapful number since it is divisible by the number (68) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638307228, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (853620768).

638307228 is an abundant number, since it is smaller than the sum of its proper divisors (1068934308).

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

638307228 is a wasteful number, since it uses less digits than its factorization.

638307228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1303 (or 1301 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 39.

The square root of 638307228 is about 25264.7427851542. The cubic root of 638307228 is about 861.0134204278.

The spelling of 638307228 in words is "six hundred thirty-eight million, three hundred seven thousand, two hundred twenty-eight".