1221131131211 has 2 divisors, whose sum is σ = 1221131131212. Its totient is φ = 1221131131210.

The previous prime is 1221131131201. The next prime is 1221131131249. The reversal of 1221131131211 is 1121311311221.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1221131131211 - 2³⁰ = 1220057389387 is a prime.

It is a super-2 number, since 2×1221131131211² (a number of 25 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (1221131131201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610565565605 + 610565565606.

It is an arithmetic number, because the mean of its divisors is an integer number (610565565606).

Almost surely, 2^{1221131131211} is an apocalyptic number.

1221131131211 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221131131211 is an equidigital number, since it uses as much as digits as its factorization.

1221131131211 is an evil number, because the sum of its binary digits is even.

The product of its digits is 72, while the sum is 20.

Adding to 1221131131211 its reverse (1121311311221), we get a palindrome (2342442442432).

The spelling of 1221131131211 in words is "one trillion, two hundred twenty-one billion, one hundred thirty-one million, one hundred thirty-one thousand, two hundred eleven".