638689250 has 16 divisors (see below), whose sum is σ = 1195626744. Its totient is φ = 255475600.

The previous prime is 638689217. The next prime is 638689253. The reversal of 638689250 is 52986836.

It is a happy number.

638689250 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 252841801 + 385847449 = 15901^2 + 19643^2 .

It is a junction number, because it is equal to n+sod(n) for n = 638689195 and 638689204.

It is not an unprimeable number, because it can be changed into a prime (638689253) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1277129 + ... + 1277628.

Almost surely, 2^638689250 is an apocalyptic number.

638689250 is a deficient number, since it is larger than the sum of its proper divisors (556937494).

638689250 is a wasteful number, since it uses less digits than its factorization.

638689250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2554774 (or 2554764 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 47.

The square root of 638689250 is about 25272.3020320666. The cubic root of 638689250 is about 861.1851561565.

The spelling of 638689250 in words is "six hundred thirty-eight million, six hundred eighty-nine thousand, two hundred fifty".