2218561 has 2 divisors, whose sum is σ = 2218562. Its totient is φ = 2218560.

The previous prime is 2218549. The next prime is 2218583. The reversal of 2218561 is 1658122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1640961 + 577600 = 1281^2 + 760^2 .

It is a cyclic number.

It is not a de Polignac number, because 2218561 - 2¹⁷ = 2087489 is a prime.

It is not a weakly prime, because it can be changed into another prime (2218361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1109280 + 1109281.

It is an arithmetic number, because the mean of its divisors is an integer number (1109281).

2^2218561 is an apocalyptic number.

It is an amenable number.

2218561 is a deficient number, since it is larger than the sum of its proper divisors (1).

2218561 is an equidigital number, since it uses as much as digits as its factorization.

2218561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 960, while the sum is 25.

The square root of 2218561 is about 1489.4834675148. The cubic root of 2218561 is about 130.4238826431.

It can be divided in two parts, 221 and 8561, that multiplied together give a palindrome (1891981).

The spelling of 2218561 in words is "two million, two hundred eighteen thousand, five hundred sixty-one".