1221243211 has 2 divisors, whose sum is σ = 1221243212. Its totient is φ = 1221243210.

The previous prime is 1221243209. The next prime is 1221243223. The reversal of 1221243211 is 1123421221.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1221243211 - 2¹ = 1221243209 is a prime.

Together with 1221243209, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1221243281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610621605 + 610621606.

It is an arithmetic number, because the mean of its divisors is an integer number (610621606).

Almost surely, 2^1221243211 is an apocalyptic number.

1221243211 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221243211 is an equidigital number, since it uses as much as digits as its factorization.

1221243211 is an evil number, because the sum of its binary digits is even.

The product of its digits is 192, while the sum is 19.

The square root of 1221243211 is about 34946.2903753746. The cubic root of 1221243211 is about 1068.8925599146.

Adding to 1221243211 its reverse (1123421221), we get a palindrome (2344664432).

The spelling of 1221243211 in words is "one billion, two hundred twenty-one million, two hundred forty-three thousand, two hundred eleven".