2661221 has 2 divisors, whose sum is σ = 2661222. Its totient is φ = 2661220.

The previous prime is 2661199. The next prime is 2661233. The reversal of 2661221 is 1221662.

It is a happy number.

2661221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2512225 + 148996 = 1585^2 + 386^2 .

It is a cyclic number.

It is not a de Polignac number, because 2661221 - 2⁶ = 2661157 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 2661193 and 2661202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2661251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1330610 + 1330611.

It is an arithmetic number, because the mean of its divisors is an integer number (1330611).

2^2661221 is an apocalyptic number.

It is an amenable number.

2661221 is a deficient number, since it is larger than the sum of its proper divisors (1).

2661221 is an equidigital number, since it uses as much as digits as its factorization.

2661221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 288, while the sum is 20.

The square root of 2661221 is about 1631.3249216511. The cubic root of 2661221 is about 138.5777951819.

Adding to 2661221 its reverse (1221662), we get a palindrome (3882883).

It can be divided in two parts, 2661 and 221, that added together give a palindrome (2882).

The spelling of 2661221 in words is "two million, six hundred sixty-one thousand, two hundred twenty-one".