212121181 has 2 divisors, whose sum is σ = 212121182. Its totient is φ = 212121180.

The previous prime is 212121179. The next prime is 212121197. The reversal of 212121181 is 181121212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 196840900 + 15280281 = 14030^2 + 3909^2 .

It is a cyclic number.

It is not a de Polignac number, because 212121181 - 2¹ = 212121179 is a prime.

It is a super-2 number, since 2×212121181² = 89990790857669522, which contains 22 as substring.

Together with 212121179, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212121781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106060590 + 106060591.

It is an arithmetic number, because the mean of its divisors is an integer number (106060591).

Almost surely, 2^212121181 is an apocalyptic number.

It is an amenable number.

212121181 is a deficient number, since it is larger than the sum of its proper divisors (1).

212121181 is an equidigital number, since it uses as much as digits as its factorization.

212121181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 64, while the sum is 19.

The square root of 212121181 is about 14564.3805566869. The cubic root of 212121181 is about 596.3867857413.

Adding to 212121181 its reverse (181121212), we get a palindrome (393242393).

The spelling of 212121181 in words is "two hundred twelve million, one hundred twenty-one thousand, one hundred eighty-one".