2188409 has 2 divisors, whose sum is σ = 2188410. Its totient is φ = 2188408.

The previous prime is 2188349. The next prime is 2188411. The reversal of 2188409 is 9048812.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1428025 + 760384 = 1195^2 + 872^2 .

It is a cyclic number.

It is not a de Polignac number, because 2188409 - 2¹⁶ = 2122873 is a prime.

Together with 2188411, it forms a pair of twin primes.

It is a Chen prime.

It is equal to p₁₆₁₈₈₈ and since 2188409 and 161888 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (2188429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1094204 + 1094205.

It is an arithmetic number, because the mean of its divisors is an integer number (1094205).

2^2188409 is an apocalyptic number.

It is an amenable number.

2188409 is a deficient number, since it is larger than the sum of its proper divisors (1).

2188409 is an equidigital number, since it uses as much as digits as its factorization.

2188409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4608, while the sum is 32.

The square root of 2188409 is about 1479.3272119447. The cubic root of 2188409 is about 129.8303309215.

The spelling of 2188409 in words is "two million, one hundred eighty-eight thousand, four hundred nine".