638882964581 has 2 divisors, whose sum is σ = 638882964582. Its totient is φ = 638882964580.

The previous prime is 638882964547. The next prime is 638882964583. The reversal of 638882964581 is 185469288836.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 568228008481 + 70654956100 = 753809^2 + 265810^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638882964581 is a prime.

It is a super-2 number, since 2×638882964581² (a number of 24 digits) contains 22 as substring.

Together with 638882964583, 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 (638882964583) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319441482290 + 319441482291.

It is an arithmetic number, because the mean of its divisors is an integer number (319441482291).

Almost surely, 2^638882964581 is an apocalyptic number.

It is an amenable number.

638882964581 is a deficient number, since it is larger than the sum of its proper divisors (1).

638882964581 is an equidigital number, since it uses as much as digits as its factorization.

638882964581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 159252480, while the sum is 68.

The spelling of 638882964581 in words is "six hundred thirty-eight billion, eight hundred eighty-two million, nine hundred sixty-four thousand, five hundred eighty-one".