2102191891 has 2 divisors, whose sum is σ = 2102191892. Its totient is φ = 2102191890.

The previous prime is 2102191873. The next prime is 2102191909. The reversal of 2102191891 is 1981912012.

It is a balanced prime because it is at equal distance from previous prime (2102191873) and next prime (2102191909).

It is a cyclic number.

It is not a de Polignac number, because 2102191891 - 2⁵ = 2102191859 is a prime.

It is not a weakly prime, because it can be changed into another prime (2102141891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1051095945 + 1051095946.

It is an arithmetic number, because the mean of its divisors is an integer number (1051095946).

Almost surely, 2^2102191891 is an apocalyptic number.

2102191891 is a deficient number, since it is larger than the sum of its proper divisors (1).

2102191891 is an equidigital number, since it uses as much as digits as its factorization.

2102191891 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2592, while the sum is 34.

The square root of 2102191891 is about 45849.6662038013. Note that the first 3 decimals coincide. The cubic root of 2102191891 is about 1281.0245481528.

The spelling of 2102191891 in words is "two billion, one hundred two million, one hundred ninety-one thousand, eight hundred ninety-one".