1211022181 has 2 divisors, whose sum is σ = 1211022182. Its totient is φ = 1211022180.

The previous prime is 1211022179. The next prime is 1211022193. The reversal of 1211022181 is 1812201121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1015441956 + 195580225 = 31866^2 + 13985^2 .

It is an emirp because it is prime and its reverse (1812201121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1211022181 - 2¹ = 1211022179 is a prime.

It is a super-2 number, since 2×1211022181² = 2933149445747993522, which contains 22 as substring.

Together with 1211022179, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1211022581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605511090 + 605511091.

It is an arithmetic number, because the mean of its divisors is an integer number (605511091).

Almost surely, 2^1211022181 is an apocalyptic number.

It is an amenable number.

1211022181 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211022181 is an equidigital number, since it uses as much as digits as its factorization.

1211022181 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 19.

The square root of 1211022181 is about 34799.7439789433. The cubic root of 1211022181 is about 1065.9022179739.

The spelling of 1211022181 in words is "one billion, two hundred eleven million, twenty-two thousand, one hundred eighty-one".