1211223281 has 2 divisors, whose sum is σ = 1211223282. Its totient is φ = 1211223280.

The previous prime is 1211223241. The next prime is 1211223283. The reversal of 1211223281 is 1823221121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 925072225 + 286151056 = 30415^2 + 16916^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211223281 - 2¹⁴ = 1211206897 is a prime.

It is a super-2 number, since 2×1211223281² = 2934123672872809922, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 1211223283, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1211223283) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605611640 + 605611641.

It is an arithmetic number, because the mean of its divisors is an integer number (605611641).

Almost surely, 2^1211223281 is an apocalyptic number.

It is an amenable number.

1211223281 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211223281 is an equidigital number, since it uses as much as digits as its factorization.

1211223281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 384, while the sum is 23.

The square root of 1211223281 is about 34802.6332480748. The cubic root of 1211223281 is about 1065.9612152616.

The spelling of 1211223281 in words is "one billion, two hundred eleven million, two hundred twenty-three thousand, two hundred eighty-one".