2102123209 has 2 divisors, whose sum is σ = 2102123210. Its totient is φ = 2102123208.

The previous prime is 2102123183. The next prime is 2102123239. The reversal of 2102123209 is 9023212012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1646087184 + 456036025 = 40572^2 + 21355^2 .

It is a cyclic number.

It is not a de Polignac number, because 2102123209 - 2²⁷ = 1967905481 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2102123209.

It is not a weakly prime, because it can be changed into another prime (2102123239) 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, 1051061604 + 1051061605.

It is an arithmetic number, because the mean of its divisors is an integer number (1051061605).

Almost surely, 2^2102123209 is an apocalyptic number.

It is an amenable number.

2102123209 is a deficient number, since it is larger than the sum of its proper divisors (1).

2102123209 is an equidigital number, since it uses as much as digits as its factorization.

2102123209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 2102123209 is about 45848.9172064074. The cubic root of 2102123209 is about 1281.0105969548.

The spelling of 2102123209 in words is "two billion, one hundred two million, one hundred twenty-three thousand, two hundred nine".