638258828 has 6 divisors (see below), whose sum is σ = 1116952956. Its totient is φ = 319129412.

The previous prime is 638258813. The next prime is 638258837. The reversal of 638258828 is 828852836.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 79782350 + ... + 79782357.

It is an arithmetic number, because the mean of its divisors is an integer number (186158826).

Almost surely, 2^638258828 is an apocalyptic number.

It is an amenable number.

638258828 is a deficient number, since it is larger than the sum of its proper divisors (478694128).

638258828 is a wasteful number, since it uses less digits than its factorization.

638258828 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159564711 (or 159564709 counting only the distinct ones).

The product of its digits is 1474560, while the sum is 50.

The square root of 638258828 is about 25263.7849104207. The cubic root of 638258828 is about 860.9916576041.

The spelling of 638258828 in words is "six hundred thirty-eight million, two hundred fifty-eight thousand, eight hundred twenty-eight".