2121320209 has 2 divisors, whose sum is σ = 2121320210. Its totient is φ = 2121320208.

The previous prime is 2121320207. The next prime is 2121320233. The reversal of 2121320209 is 9020231212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1566576400 + 554743809 = 39580^2 + 23553^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121320209 - 2¹ = 2121320207 is a prime.

It is a super-2 number, since 2×2121320209² = 8999998858223607362, which contains 22 as substring.

Together with 2121320207, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 2121320209.

It is not a weakly prime, because it can be changed into another prime (2121320207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1060660104 + 1060660105.

It is an arithmetic number, because the mean of its divisors is an integer number (1060660105).

Almost surely, 2^2121320209 is an apocalyptic number.

It is an amenable number.

2121320209 is a deficient number, since it is larger than the sum of its proper divisors (1).

2121320209 is an equidigital number, since it uses as much as digits as its factorization.

2121320209 is an evil number, because the sum of its binary digits is even.

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

The square root of 2121320209 is about 46057.7920551995. The cubic root of 2121320209 is about 1284.8982662574.

The spelling of 2121320209 in words is "two billion, one hundred twenty-one million, three hundred twenty thousand, two hundred nine".