1221211231 has 2 divisors, whose sum is σ = 1221211232. Its totient is φ = 1221211230.

The previous prime is 1221211181. The next prime is 1221211237. The reversal of 1221211231 is 1321121221.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1221211231 - 2²³ = 1212822623 is a prime.

It is a super-2 number, since 2×1221211231² = 2982713741441070722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221211237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610605615 + 610605616.

It is an arithmetic number, because the mean of its divisors is an integer number (610605616).

Almost surely, 2^1221211231 is an apocalyptic number.

1221211231 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221211231 is an equidigital number, since it uses as much as digits as its factorization.

1221211231 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48, while the sum is 16.

The square root of 1221211231 is about 34945.8328130837. The cubic root of 1221211231 is about 1068.8832296730.

Adding to 1221211231 its reverse (1321121221), we get a palindrome (2542332452).

The spelling of 1221211231 in words is "one billion, two hundred twenty-one million, two hundred eleven thousand, two hundred thirty-one".