638408193 has 4 divisors (see below), whose sum is σ = 851210928. Its totient is φ = 425605460.

The previous prime is 638408179. The next prime is 638408201. The reversal of 638408193 is 391804836.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 638408193 - 2⁶ = 638408129 is a prime.

It is not an unprimeable number, because it can be changed into a prime (638408153) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 106401363 + ... + 106401368.

It is an arithmetic number, because the mean of its divisors is an integer number (212802732).

Almost surely, 2^638408193 is an apocalyptic number.

It is an amenable number.

638408193 is a deficient number, since it is larger than the sum of its proper divisors (212802735).

638408193 is a wasteful number, since it uses less digits than its factorization.

638408193 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 212802734.

The product of its (nonzero) digits is 124416, while the sum is 42.

The square root of 638408193 is about 25266.7408464171. The cubic root of 638408193 is about 861.0588153061.

The spelling of 638408193 in words is "six hundred thirty-eight million, four hundred eight thousand, one hundred ninety-three".