26638989697 has 2 divisors, whose sum is σ = 26638989698. Its totient is φ = 26638989696.

The previous prime is 26638989659. The next prime is 26638989721. The reversal of 26638989697 is 79698983662.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 26606829456 + 32160241 = 163116^2 + 5671^2 .

It is a cyclic number.

It is not a de Polignac number, because 26638989697 - 2¹⁹ = 26638465409 is a prime.

It is not a weakly prime, because it can be changed into another prime (26638989497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13319494848 + 13319494849.

It is an arithmetic number, because the mean of its divisors is an integer number (13319494849).

Almost surely, 2^26638989697 is an apocalyptic number.

It is an amenable number.

26638989697 is a deficient number, since it is larger than the sum of its proper divisors (1).

26638989697 is an equidigital number, since it uses as much as digits as its factorization.

26638989697 is an evil number, because the sum of its binary digits is even.

The product of its digits is 423263232, while the sum is 73.

The spelling of 26638989697 in words is "twenty-six billion, six hundred thirty-eight million, nine hundred eighty-nine thousand, six hundred ninety-seven".