638944455 has 16 divisors (see below), whose sum is σ = 1022706144. Its totient is φ = 340638720.

The previous prime is 638944447. The next prime is 638944457. The reversal of 638944455 is 554449836.

It is not a de Polignac number, because 638944455 - 2³ = 638944447 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638944457) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 41635 + ... + 54875.

It is an arithmetic number, because the mean of its divisors is an integer number (63919134).

Almost surely, 2^638944455 is an apocalyptic number.

638944455 is a deficient number, since it is larger than the sum of its proper divisors (383761689).

638944455 is a wasteful number, since it uses less digits than its factorization.

638944455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16466.

The product of its digits is 2073600, while the sum is 48.

The square root of 638944455 is about 25277.3506325327. The cubic root of 638944455 is about 861.2998439025.

The spelling of 638944455 in words is "six hundred thirty-eight million, nine hundred forty-four thousand, four hundred fifty-five".