638220328 has 8 divisors (see below), whose sum is σ = 1196663130. Its totient is φ = 319110160.

The previous prime is 638220293. The next prime is 638220347. The reversal of 638220328 is 823022836.

It can be written as a sum of positive squares in only one way, i.e., 388011204 + 250209124 = 19698^2 + 15818^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 638220293 and 638220302.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39888763 + ... + 39888778.

Almost surely, 2^638220328 is an apocalyptic number.

It is an amenable number.

638220328 is a deficient number, since it is larger than the sum of its proper divisors (558442802).

638220328 is a wasteful number, since it uses less digits than its factorization.

638220328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79777547 (or 79777543 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 34.

The square root of 638220328 is about 25263.0229386746. The cubic root of 638220328 is about 860.9743454815.

The spelling of 638220328 in words is "six hundred thirty-eight million, two hundred twenty thousand, three hundred twenty-eight".