26561221 has 4 divisors (see below), whose sum is σ = 27959200. Its totient is φ = 25163244.

The previous prime is 26561201. The next prime is 26561231. The reversal of 26561221 is 12216562.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 26561221 - 2⁵ = 26561189 is a prime.

It is a super-2 number, since 2×26561221² = 1410996922021682, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (26561201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 698961 + ... + 698998.

It is an arithmetic number, because the mean of its divisors is an integer number (6989800).

Almost surely, 2^26561221 is an apocalyptic number.

It is an amenable number.

26561221 is a deficient number, since it is larger than the sum of its proper divisors (1397979).

26561221 is a wasteful number, since it uses less digits than its factorization.

26561221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1397978.

The product of its digits is 1440, while the sum is 25.

The square root of 26561221 is about 5153.7579493026. The cubic root of 26561221 is about 298.3660089952.

Adding to 26561221 its reverse (12216562), we get a palindrome (38777783).

The spelling of 26561221 in words is "twenty-six million, five hundred sixty-one thousand, two hundred twenty-one".