26661221 has 2 divisors, whose sum is σ = 26661222. Its totient is φ = 26661220.

The previous prime is 26661197. The next prime is 26661227. The reversal of 26661221 is 12216662.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24453025 + 2208196 = 4945^2 + 1486^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-26661221 is a prime.

It is a Chen prime.

It is equal to p_1663253 and since 26661221 and 1663253 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (26661227) 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, 13330610 + 13330611.

It is an arithmetic number, because the mean of its divisors is an integer number (13330611).

Almost surely, 2^26661221 is an apocalyptic number.

It is an amenable number.

26661221 is a deficient number, since it is larger than the sum of its proper divisors (1).

26661221 is an equidigital number, since it uses as much as digits as its factorization.

26661221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1728, while the sum is 26.

The square root of 26661221 is about 5163.4504936137. The cubic root of 26661221 is about 298.7399781889.

Adding to 26661221 its reverse (12216662), we get a palindrome (38877883).

The spelling of 26661221 in words is "twenty-six million, six hundred sixty-one thousand, two hundred twenty-one".