638763775 has 12 divisors (see below), whose sum is σ = 852995752. Its totient is φ = 471702240.

The previous prime is 638763739. The next prime is 638763779. The reversal of 638763775 is 577367836.

It is a happy number.

It is not a de Polignac number, because 638763775 - 2²⁵ = 605209343 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638763779) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 982389 + ... + 983038.

Almost surely, 2^638763775 is an apocalyptic number.

638763775 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

638763775 is a deficient number, since it is larger than the sum of its proper divisors (214231977).

638763775 is a wasteful number, since it uses less digits than its factorization.

638763775 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1965450 (or 1965445 counting only the distinct ones).

The product of its digits is 4445280, while the sum is 52.

The square root of 638763775 is about 25273.7764293348. The cubic root of 638763775 is about 861.2186504458.

The spelling of 638763775 in words is "six hundred thirty-eight million, seven hundred sixty-three thousand, seven hundred seventy-five".