2021609 has 2 divisors, whose sum is σ = 2021610. Its totient is φ = 2021608.

The previous prime is 2021599. The next prime is 2021627. The reversal of 2021609 is 9061202.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1373584 + 648025 = 1172^2 + 805^2 .

It is a cyclic number.

It is not a de Polignac number, because 2021609 - 2¹² = 2017513 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (2021629) 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, 1010804 + 1010805.

It is an arithmetic number, because the mean of its divisors is an integer number (1010805).

2^2021609 is an apocalyptic number.

It is an amenable number.

2021609 is a deficient number, since it is larger than the sum of its proper divisors (1).

2021609 is an equidigital number, since it uses as much as digits as its factorization.

2021609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 2021609 is about 1421.8329719063. The cubic root of 2021609 is about 126.4442410762. Note that the first 3 decimals are identical.

The spelling of 2021609 in words is "two million, twenty-one thousand, six hundred nine".