638606938 has 8 divisors (see below), whose sum is σ = 1014258132. Its totient is φ = 300520896.

The previous prime is 638606879. The next prime is 638606963. The reversal of 638606938 is 839606836.

It can be written as a sum of positive squares in 2 ways, for example, as 603832329 + 34774609 = 24573^2 + 5897^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 638606891 and 638606900.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9391245 + ... + 9391312.

Almost surely, 2^638606938 is an apocalyptic number.

638606938 is a deficient number, since it is larger than the sum of its proper divisors (375651194).

638606938 is a wasteful number, since it uses less digits than its factorization.

638606938 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18782576.

The product of its (nonzero) digits is 1119744, while the sum is 49.

The square root of 638606938 is about 25270.6734773729. The cubic root of 638606938 is about 861.1481590733.

The spelling of 638606938 in words is "six hundred thirty-eight million, six hundred six thousand, nine hundred thirty-eight".