201221101181 has 2 divisors, whose sum is σ = 201221101182. Its totient is φ = 201221101180.

The previous prime is 201221101087. The next prime is 201221101243. The reversal of 201221101181 is 181101122102.

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., 200785544281 + 435556900 = 448091^2 + 20870^2 .

It is a cyclic number.

It is not a de Polignac number, because 201221101181 - 2¹⁴ = 201221084797 is a prime.

It is a super-2 number, since 2×201221101181² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201221121181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100610550590 + 100610550591.

It is an arithmetic number, because the mean of its divisors is an integer number (100610550591).

Almost surely, 2^201221101181 is an apocalyptic number.

It is an amenable number.

201221101181 is a deficient number, since it is larger than the sum of its proper divisors (1).

201221101181 is an equidigital number, since it uses as much as digits as its factorization.

201221101181 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64, while the sum is 20.

Adding to 201221101181 its reverse (181101122102), we get a palindrome (382322223283).

The spelling of 201221101181 in words is "two hundred one billion, two hundred twenty-one million, one hundred one thousand, one hundred eighty-one".