2161231109 has 2 divisors, whose sum is σ = 2161231110. Its totient is φ = 2161231108.

The previous prime is 2161231103. The next prime is 2161231117. The reversal of 2161231109 is 9011321612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2117380225 + 43850884 = 46015^2 + 6622^2 .

It is a cyclic number.

It is not a de Polignac number, because 2161231109 - 2²⁴ = 2144453893 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2161231103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1080615554 + 1080615555.

It is an arithmetic number, because the mean of its divisors is an integer number (1080615555).

Almost surely, 2^2161231109 is an apocalyptic number.

It is an amenable number.

2161231109 is a deficient number, since it is larger than the sum of its proper divisors (1).

2161231109 is an equidigital number, since it uses as much as digits as its factorization.

2161231109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 26.

The square root of 2161231109 is about 46489.0428918471. The cubic root of 2161231109 is about 1292.9063547773.

The spelling of 2161231109 in words is "two billion, one hundred sixty-one million, two hundred thirty-one thousand, one hundred nine".