26663561 has 2 divisors, whose sum is σ = 26663562. Its totient is φ = 26663560.

The previous prime is 26663519. The next prime is 26663563. The reversal of 26663561 is 16536662.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 26327161 + 336400 = 5131^2 + 580^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-26663561 is a prime.

It is a Sophie Germain prime.

Together with 26663563, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (26663563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13331780 + 13331781.

It is an arithmetic number, because the mean of its divisors is an integer number (13331781).

Almost surely, 2^26663561 is an apocalyptic number.

It is an amenable number.

26663561 is a deficient number, since it is larger than the sum of its proper divisors (1).

26663561 is an equidigital number, since it uses as much as digits as its factorization.

26663561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 38880, while the sum is 35.

The square root of 26663561 is about 5163.6770813055. The cubic root of 26663561 is about 298.7487178624.

The spelling of 26663561 in words is "twenty-six million, six hundred sixty-three thousand, five hundred sixty-one".