1221031211 has 2 divisors, whose sum is σ = 1221031212. Its totient is φ = 1221031210.

The previous prime is 1221031187. The next prime is 1221031241. The reversal of 1221031211 is 1121301221.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221031211 is a prime.

It is a super-2 number, since 2×1221031211² = 2981834436472253042, which contains 22 as substring.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (1221031241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610515605 + 610515606.

It is an arithmetic number, because the mean of its divisors is an integer number (610515606).

Almost surely, 2^1221031211 is an apocalyptic number.

1221031211 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221031211 is an equidigital number, since it uses as much as digits as its factorization.

1221031211 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24, while the sum is 14.

The square root of 1221031211 is about 34943.2570176279. The cubic root of 1221031211 is about 1068.8307053677.

Adding to 1221031211 its reverse (1121301221), we get a palindrome (2342332432).

The spelling of 1221031211 in words is "one billion, two hundred twenty-one million, thirty-one thousand, two hundred eleven".