638494235 has 4 divisors (see below), whose sum is σ = 766193088. Its totient is φ = 510795384.

The previous prime is 638494231. The next prime is 638494243. The reversal of 638494235 is 532494836.

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

It is a cyclic number.

It is not a de Polignac number, because 638494235 - 2² = 638494231 is a prime.

It is a Duffinian 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 in 3 ways as a sum of consecutive naturals, for example, 63849419 + ... + 63849428.

It is an arithmetic number, because the mean of its divisors is an integer number (191548272).

Almost surely, 2^638494235 is an apocalyptic number.

638494235 is a deficient number, since it is larger than the sum of its proper divisors (127698853).

638494235 is a wasteful number, since it uses less digits than its factorization.

638494235 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127698852.

The product of its digits is 622080, while the sum is 44.

The square root of 638494235 is about 25268.4434621526. The cubic root of 638494235 is about 861.0974968765.

The spelling of 638494235 in words is "six hundred thirty-eight million, four hundred ninety-four thousand, two hundred thirty-five".