26685665781917 has 2 divisors, whose sum is σ = 26685665781918. Its totient is φ = 26685665781916.

The previous prime is 26685665781913. The next prime is 26685665781941. The reversal of 26685665781917 is 71918756658662.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 26658159227716 + 27506554201 = 5163154^2 + 165851^2 .

It is a cyclic number.

It is not a de Polignac number, because 26685665781917 - 2² = 26685665781913 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (26685665781913) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13342832890958 + 13342832890959.

It is an arithmetic number, because the mean of its divisors is an integer number (13342832890959).

Almost surely, 2^{26685665781917} is an apocalyptic number.

It is an amenable number.

26685665781917 is a deficient number, since it is larger than the sum of its proper divisors (1).

26685665781917 is an equidigital number, since it uses as much as digits as its factorization.

26685665781917 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1828915200, while the sum is 77.

The spelling of 26685665781917 in words is "twenty-six trillion, six hundred eighty-five billion, six hundred sixty-five million, seven hundred eighty-one thousand, nine hundred seventeen".