2189181809 has 2 divisors, whose sum is σ = 2189181810. Its totient is φ = 2189181808.

The previous prime is 2189181803. The next prime is 2189181811. The reversal of 2189181809 is 9081819812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2021401600 + 167780209 = 44960^2 + 12953^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2189181809 is a prime.

Together with 2189181811, 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 (2189181803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1094590904 + 1094590905.

It is an arithmetic number, because the mean of its divisors is an integer number (1094590905).

Almost surely, 2^2189181809 is an apocalyptic number.

It is an amenable number.

2189181809 is a deficient number, since it is larger than the sum of its proper divisors (1).

2189181809 is an equidigital number, since it uses as much as digits as its factorization.

2189181809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 82944, while the sum is 47.

The square root of 2189181809 is about 46788.6931747404. The cubic root of 2189181809 is about 1298.4561177016.

The spelling of 2189181809 in words is "two billion, one hundred eighty-nine million, one hundred eighty-one thousand, eight hundred nine".