2209561 has 4 divisors (see below), whose sum is σ = 2214324. Its totient is φ = 2204800.

The previous prime is 2209549. The next prime is 2209579. The reversal of 2209561 is 1659022.

2209561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1659022 = 2 ⋅829511.

It can be written as a sum of positive squares in 2 ways, for example, as 1577536 + 632025 = 1256^2 + 795^2 .

It is a cyclic number.

It is not a de Polignac number, because 2209561 - 2⁹ = 2209049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2209511) 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 in 3 ways as a sum of consecutive naturals, for example, 1600 + ... + 2641.

It is an arithmetic number, because the mean of its divisors is an integer number (553581).

2^2209561 is an apocalyptic number.

It is an amenable number.

2209561 is a deficient number, since it is larger than the sum of its proper divisors (4763).

2209561 is an equidigital number, since it uses as much as digits as its factorization.

2209561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4762.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 2209561 is about 1486.4592157204. The cubic root of 2209561 is about 130.2472808134.

The spelling of 2209561 in words is "two million, two hundred nine thousand, five hundred sixty-one".