2116561 has 2 divisors, whose sum is σ = 2116562. Its totient is φ = 2116560.

The previous prime is 2116559. The next prime is 2116571. The reversal of 2116561 is 1656112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1404225 + 712336 = 1185^2 + 844^2 .

It is a cyclic number.

It is not a de Polignac number, because 2116561 - 2¹ = 2116559 is a prime.

Together with 2116559, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (2116501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1058280 + 1058281.

It is an arithmetic number, because the mean of its divisors is an integer number (1058281).

2^2116561 is an apocalyptic number.

It is an amenable number.

2116561 is a deficient number, since it is larger than the sum of its proper divisors (1).

2116561 is an equidigital number, since it uses as much as digits as its factorization.

2116561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 360, while the sum is 22.

The square root of 2116561 is about 1454.8405410903. The cubic root of 2116561 is about 128.3936651540.

The spelling of 2116561 in words is "two million, one hundred sixteen thousand, five hundred sixty-one".