638494238 has 4 divisors (see below), whose sum is σ = 957741360. Its totient is φ = 319247118.

The previous prime is 638494231. The next prime is 638494243. The reversal of 638494238 is 832494836.

It is a semiprime because it is the product of two primes.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 638494192 and 638494201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638494231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 159623558 + ... + 159623561.

It is an arithmetic number, because the mean of its divisors is an integer number (239435340).

Almost surely, 2^638494238 is an apocalyptic number.

638494238 is a deficient number, since it is larger than the sum of its proper divisors (319247122).

638494238 is a wasteful number, since it uses less digits than its factorization.

638494238 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 319247121.

The product of its digits is 995328, while the sum is 47.

The square root of 638494238 is about 25268.4435215151. The cubic root of 638494238 is about 861.0974982252.

The spelling of 638494238 in words is "six hundred thirty-eight million, four hundred ninety-four thousand, two hundred thirty-eight".