201221101 has 2 divisors, whose sum is σ = 201221102. Its totient is φ = 201221100.

The previous prime is 201221099. The next prime is 201221113. The reversal of 201221101 is 101122102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 177688900 + 23532201 = 13330^2 + 4851^2 .

It is a cyclic number.

It is not a de Polignac number, because 201221101 - 2¹ = 201221099 is a prime.

Together with 201221099, 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 (201221161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100610550 + 100610551.

It is an arithmetic number, because the mean of its divisors is an integer number (100610551).

Almost surely, 2^201221101 is an apocalyptic number.

It is an amenable number.

201221101 is a deficient number, since it is larger than the sum of its proper divisors (1).

201221101 is an equidigital number, since it uses as much as digits as its factorization.

201221101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 201221101 is about 14185.2423666288. The cubic root of 201221101 is about 585.9913072829.

Adding to 201221101 its reverse (101122102), we get a palindrome (302343203).

The spelling of 201221101 in words is "two hundred one million, two hundred twenty-one thousand, one hundred one".