638028772 has 6 divisors (see below), whose sum is σ = 1116550358. Its totient is φ = 319014384.

The previous prime is 638028761. The next prime is 638028779. The reversal of 638028772 is 277820836.

It can be written as a sum of positive squares in only one way, i.e., 517380516 + 120648256 = 22746^2 + 10984^2 .

It is not an unprimeable number, because it can be changed into a prime (638028779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 79753593 + ... + 79753600.

Almost surely, 2^638028772 is an apocalyptic number.

It is an amenable number.

638028772 is a deficient number, since it is larger than the sum of its proper divisors (478521586).

638028772 is a wasteful number, since it uses less digits than its factorization.

638028772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159507197 (or 159507195 counting only the distinct ones).

The product of its (nonzero) digits is 225792, while the sum is 43.

The square root of 638028772 is about 25259.2314214031. The cubic root of 638028772 is about 860.8881990012. Note that the first 3 decimals are identical.

The spelling of 638028772 in words is "six hundred thirty-eight million, twenty-eight thousand, seven hundred seventy-two".