221200121 has 2 divisors, whose sum is σ = 221200122. Its totient is φ = 221200120.

The previous prime is 221200093. The next prime is 221200123. The reversal of 221200121 is 121002122.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 194212096 + 26988025 = 13936^2 + 5195^2 .

It is a cyclic number.

It is not a de Polignac number, because 221200121 - 2¹⁴ = 221183737 is a prime.

Together with 221200123, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (221200123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110600060 + 110600061.

It is an arithmetic number, because the mean of its divisors is an integer number (110600061).

Almost surely, 2^221200121 is an apocalyptic number.

It is an amenable number.

221200121 is a deficient number, since it is larger than the sum of its proper divisors (1).

221200121 is an equidigital number, since it uses as much as digits as its factorization.

221200121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 221200121 is about 14872.7980218922. The cubic root of 221200121 is about 604.7767962917.

Adding to 221200121 its reverse (121002122), we get a palindrome (342202243).

The spelling of 221200121 in words is "two hundred twenty-one million, two hundred thousand, one hundred twenty-one".