26561231 has 2 divisors, whose sum is σ = 26561232. Its totient is φ = 26561230.

The previous prime is 26561201. The next prime is 26561243. The reversal of 26561231 is 13216562.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-26561231 is a prime.

It is a super-2 number, since 2×26561231² = 1410997984470722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is equal to p_1657430 and since 26561231 and 1657430 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 26561231.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (26561201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13280615 + 13280616.

It is an arithmetic number, because the mean of its divisors is an integer number (13280616).

Almost surely, 2^26561231 is an apocalyptic number.

26561231 is a deficient number, since it is larger than the sum of its proper divisors (1).

26561231 is an equidigital number, since it uses as much as digits as its factorization.

26561231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2160, while the sum is 26.

The square root of 26561231 is about 5153.7589194684. The cubic root of 26561231 is about 298.3660464390.

Adding to 26561231 its reverse (13216562), we get a palindrome (39777793).

The spelling of 26561231 in words is "twenty-six million, five hundred sixty-one thousand, two hundred thirty-one".