1891105189 has 2 divisors, whose sum is σ = 1891105190. Its totient is φ = 1891105188.

The previous prime is 1891105163. The next prime is 1891105193. The reversal of 1891105189 is 9815011981.

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., 1879916164 + 11189025 = 43358^2 + 3345^2 .

It is a cyclic number.

It is not a de Polignac number, because 1891105189 - 2⁵ = 1891105157 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1891105199) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 945552594 + 945552595.

It is an arithmetic number, because the mean of its divisors is an integer number (945552595).

Almost surely, 2^1891105189 is an apocalyptic number.

It is an amenable number.

1891105189 is a deficient number, since it is larger than the sum of its proper divisors (1).

1891105189 is an equidigital number, since it uses as much as digits as its factorization.

1891105189 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 43.

The square root of 1891105189 is about 43486.8392620112. The cubic root of 1891105189 is about 1236.6265376490.

The spelling of 1891105189 in words is "one billion, eight hundred ninety-one million, one hundred five thousand, one hundred eighty-nine".