2011211221 has 2 divisors, whose sum is σ = 2011211222.
Its totient is φ = 2011211220.
The previous prime is 2011211207. The next prime is 2011211239. The reversal of 2011211221 is 1221121102.
It is a weak prime.
It can be written as a sum of positive squares in only one way, i.e., 1773588996 + 237622225 = 42114^2 + 15415^2
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-2011211221 is a prime.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (2011211261) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1005605610 + 1005605611.
It is an arithmetic number, because the mean of its divisors is an integer number (1005605611).
Almost surely, 22011211221 is an apocalyptic number.
It is an amenable number.
2011211221 is a deficient number, since it is larger than the sum of its proper divisors (1).
2011211221 is an equidigital number, since it uses as much as digits as its factorization.
2011211221 is an evil number, because the sum of its binary digits is even.
The product of its (nonzero) digits is 16, while the sum is 13.
The square root of 2011211221 is about 44846.5296427717.
The cubic root of 2011211221 is about 1262.2708735059.
Adding to 2011211221 its reverse (1221121102), we get a palindrome (3232332323).
The spelling of 2011211221 in words is "two billion, eleven million, two hundred eleven thousand, two hundred twenty-one".