638994291 has 16 divisors (see below), whose sum is σ = 918296064. Its totient is φ = 392899104.

The previous prime is 638994269. The next prime is 638994347. The reversal of 638994291 is 192499836.

638994291 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 638994291 - 2⁷ = 638994163 is a prime.

It is not an unprimeable number, because it can be changed into a prime (638996291) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 45580 + ... + 57926.

It is an arithmetic number, because the mean of its divisors is an integer number (57393504).

Almost surely, 2^638994291 is an apocalyptic number.

638994291 is a deficient number, since it is larger than the sum of its proper divisors (279301773).

638994291 is a wasteful number, since it uses less digits than its factorization.

638994291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13690.

The product of its digits is 839808, while the sum is 51.

The square root of 638994291 is about 25278.3363970021. The cubic root of 638994291 is about 861.3222363670.

The spelling of 638994291 in words is "six hundred thirty-eight million, nine hundred ninety-four thousand, two hundred ninety-one".