2102191909 has 2 divisors, whose sum is σ = 2102191910. Its totient is φ = 2102191908.

The previous prime is 2102191891. The next prime is 2102191913. The reversal of 2102191909 is 9091912012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1833723684 + 268468225 = 42822^2 + 16385^2 .

It is a cyclic number.

It is not a de Polignac number, because 2102191909 - 2¹⁵ = 2102159141 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2102191919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1051095954 + 1051095955.

It is an arithmetic number, because the mean of its divisors is an integer number (1051095955).

Almost surely, 2^2102191909 is an apocalyptic number.

It is an amenable number.

2102191909 is a deficient number, since it is larger than the sum of its proper divisors (1).

2102191909 is an equidigital number, since it uses as much as digits as its factorization.

2102191909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2916, while the sum is 34.

The square root of 2102191909 is about 45849.6664000950. Note that the first 3 decimals coincide. The cubic root of 2102191909 is about 1281.0245518091.

The spelling of 2102191909 in words is "two billion, one hundred two million, one hundred ninety-one thousand, nine hundred nine".