2638888888681 has 2 divisors, whose sum is σ = 2638888888682. Its totient is φ = 2638888888680.

The previous prime is 2638888888679. The next prime is 2638888888813. The reversal of 2638888888681 is 1868888888362.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2036588722281 + 602300166400 = 1427091^2 + 776080^2 .

It is a cyclic number.

It is not a de Polignac number, because 2638888888681 - 2¹ = 2638888888679 is a prime.

It is a super-2 number, since 2×2638888888681² (a number of 26 digits) contains 22 as substring.

Together with 2638888888679, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 2638888888595 and 2638888888604.

It is not a weakly prime, because it can be changed into another prime (2638888888381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1319444444340 + 1319444444341.

It is an arithmetic number, because the mean of its divisors is an integer number (1319444444341).

Almost surely, 2^{2638888888681} is an apocalyptic number.

It is an amenable number.

2638888888681 is a deficient number, since it is larger than the sum of its proper divisors (1).

2638888888681 is an equidigital number, since it uses as much as digits as its factorization.

2638888888681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3623878656, while the sum is 82.

The spelling of 2638888888681 in words is "two trillion, six hundred thirty-eight billion, eight hundred eighty-eight million, eight hundred eighty-eight thousand, six hundred eighty-one".