2190809 has 2 divisors, whose sum is σ = 2190810. Its totient is φ = 2190808.

The previous prime is 2190763. The next prime is 2190817. The reversal of 2190809 is 9080912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2166784 + 24025 = 1472^2 + 155^2 .

It is a cyclic number.

It is not a de Polignac number, because 2190809 - 2¹² = 2186713 is a prime.

It is not a weakly prime, because it can be changed into another prime (2190829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1095404 + 1095405.

It is an arithmetic number, because the mean of its divisors is an integer number (1095405).

2^2190809 is an apocalyptic number.

It is an amenable number.

2190809 is a deficient number, since it is larger than the sum of its proper divisors (1).

2190809 is an equidigital number, since it uses as much as digits as its factorization.

2190809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1296, while the sum is 29.

The square root of 2190809 is about 1480.1381692261. The cubic root of 2190809 is about 129.8777746667.

The spelling of 2190809 in words is "two million, one hundred ninety thousand, eight hundred nine".