212121212209 has 2 divisors, whose sum is σ = 212121212210. Its totient is φ = 212121212208.

The previous prime is 212121212183. The next prime is 212121212257. The reversal of 212121212209 is 902212121212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 157565333025 + 54555879184 = 396945^2 + 233572^2 .

It is a cyclic number.

It is not a de Polignac number, because 212121212209 - 2⁹ = 212121211697 is a prime.

It is a super-2 number, since 2×212121212209² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (212121212299) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106060606104 + 106060606105.

It is an arithmetic number, because the mean of its divisors is an integer number (106060606105).

Almost surely, 2^212121212209 is an apocalyptic number.

It is an amenable number.

212121212209 is a deficient number, since it is larger than the sum of its proper divisors (1).

212121212209 is an equidigital number, since it uses as much as digits as its factorization.

212121212209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 25.

The spelling of 212121212209 in words is "two hundred twelve billion, one hundred twenty-one million, two hundred twelve thousand, two hundred nine".