26201561 has 2 divisors, whose sum is σ = 26201562. Its totient is φ = 26201560.

The previous prime is 26201533. The next prime is 26201563. The reversal of 26201561 is 16510262.

26201561 = 3619² + 3620².

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13104400 + 13097161 = 3620^2 + 3619^2 .

It is a cyclic number.

It is not a de Polignac number, because 26201561 - 2¹⁴ = 26185177 is a prime.

Together with 26201563, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (26201563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13100780 + 13100781.

It is an arithmetic number, because the mean of its divisors is an integer number (13100781).

Almost surely, 2^26201561 is an apocalyptic number.

26201561 is the 3620-th centered square number.

It is an amenable number.

26201561 is a deficient number, since it is larger than the sum of its proper divisors (1).

26201561 is an equidigital number, since it uses as much as digits as its factorization.

26201561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 26201561 is about 5118.7460378495. The cubic root of 26201561 is about 297.0131802319.

It can be divided in two parts, 26201 and 561, that added together give a palindrome (26762).

The spelling of 26201561 in words is "twenty-six million, two hundred one thousand, five hundred sixty-one".