638262935509 has 2 divisors, whose sum is σ = 638262935510. Its totient is φ = 638262935508.

The previous prime is 638262935447. The next prime is 638262935549. The reversal of 638262935509 is 905539262836.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 515671918609 + 122591016900 = 718103^2 + 350130^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638262935509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638262935549) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319131467754 + 319131467755.

It is an arithmetic number, because the mean of its divisors is an integer number (319131467755).

Almost surely, 2^638262935509 is an apocalyptic number.

It is an amenable number.

638262935509 is a deficient number, since it is larger than the sum of its proper divisors (1).

638262935509 is an equidigital number, since it uses as much as digits as its factorization.

638262935509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20995200, while the sum is 58.

The spelling of 638262935509 in words is "six hundred thirty-eight billion, two hundred sixty-two million, nine hundred thirty-five thousand, five hundred nine".