2121012021209 has 2 divisors, whose sum is σ = 2121012021210. Its totient is φ = 2121012021208.

The previous prime is 2121012021181. The next prime is 2121012021259. The reversal of 2121012021209 is 9021202101212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1594512307600 + 526499713609 = 1262740^2 + 725603^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121012021209 - 2²⁴ = 2120995243993 is a prime.

It is a super-2 number, since 2×2121012021209² (a number of 25 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (2121012021259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1060506010604 + 1060506010605.

It is an arithmetic number, because the mean of its divisors is an integer number (1060506010605).

Almost surely, 2^{2121012021209} is an apocalyptic number.

It is an amenable number.

2121012021209 is a deficient number, since it is larger than the sum of its proper divisors (1).

2121012021209 is an equidigital number, since it uses as much as digits as its factorization.

2121012021209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 23.

The spelling of 2121012021209 in words is "two trillion, one hundred twenty-one billion, twelve million, twenty-one thousand, two hundred nine".