638117775 has 18 divisors (see below), whose sum is σ = 1142940240. Its totient is φ = 340329360.

The previous prime is 638117771. The next prime is 638117789. The reversal of 638117775 is 577711836.

638117775 is a `hidden beast` number, since 638 + 1 + 1 + 7 + 7 + 7 + 5 = 666.

638117775 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 638117775 - 2² = 638117771 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 638117775.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638117771) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1417815 + ... + 1418264.

It is an arithmetic number, because the mean of its divisors is an integer number (63496680).

Almost surely, 2^638117775 is an apocalyptic number.

638117775 is a deficient number, since it is larger than the sum of its proper divisors (504822465).

638117775 is a wasteful number, since it uses less digits than its factorization.

638117775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2836095 (or 2836087 counting only the distinct ones).

The product of its digits is 246960, while the sum is 45.

The square root of 638117775 is about 25260.9931514974. The cubic root of 638117775 is about 860.9282275355.

The spelling of 638117775 in words is "six hundred thirty-eight million, one hundred seventeen thousand, seven hundred seventy-five".