1921109189 has 2 divisors, whose sum is σ = 1921109190. Its totient is φ = 1921109188.

The previous prime is 1921109107. The next prime is 1921109219. The reversal of 1921109189 is 9819011291.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1639440100 + 281669089 = 40490^2 + 16783^2 .

It is a cyclic number.

It is not a de Polignac number, because 1921109189 - 2²⁰ = 1920060613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1921100189) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 960554594 + 960554595.

It is an arithmetic number, because the mean of its divisors is an integer number (960554595).

Almost surely, 2^1921109189 is an apocalyptic number.

It is an amenable number.

1921109189 is a deficient number, since it is larger than the sum of its proper divisors (1).

1921109189 is an equidigital number, since it uses as much as digits as its factorization.

1921109189 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11664, while the sum is 41.

The square root of 1921109189 is about 43830.4596028835. The cubic root of 1921109189 is about 1243.1322971484.

The spelling of 1921109189 in words is "one billion, nine hundred twenty-one million, one hundred nine thousand, one hundred eighty-nine".