638613782669 has 2 divisors, whose sum is σ = 638613782670. Its totient is φ = 638613782668.

The previous prime is 638613782647. The next prime is 638613782671. The reversal of 638613782669 is 966287316836.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 590208062500 + 48405720169 = 768250^2 + 220013^2 .

It is a cyclic number.

It is not a de Polignac number, because 638613782669 - 2⁸ = 638613782413 is a prime.

It is a super-2 number, since 2×638613782669² (a number of 24 digits) contains 22 as substring.

Together with 638613782671, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638613782629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319306891334 + 319306891335.

It is an arithmetic number, because the mean of its divisors is an integer number (319306891335).

Almost surely, 2^638613782669 is an apocalyptic number.

It is an amenable number.

638613782669 is a deficient number, since it is larger than the sum of its proper divisors (1).

638613782669 is an equidigital number, since it uses as much as digits as its factorization.

638613782669 is an evil number, because the sum of its binary digits is even.

The product of its digits is 94058496, while the sum is 65.

The spelling of 638613782669 in words is "six hundred thirty-eight billion, six hundred thirteen million, seven hundred eighty-two thousand, six hundred sixty-nine".