1221131111311 has 2 divisors, whose sum is σ = 1221131111312. Its totient is φ = 1221131111310.

The previous prime is 1221131111309. The next prime is 1221131111323. The reversal of 1221131111311 is 1131111311221.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1221131111311 - 2¹ = 1221131111309 is a prime.

It is a super-2 number, since 2×1221131111311² (a number of 25 digits) contains 22 as substring.

Together with 1221131111309, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221131151311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610565555655 + 610565555656.

It is an arithmetic number, because the mean of its divisors is an integer number (610565555656).

Almost surely, 2^{1221131111311} is an apocalyptic number.

1221131111311 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221131111311 is an equidigital number, since it uses as much as digits as its factorization.

1221131111311 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36, while the sum is 19.

Adding to 1221131111311 its reverse (1131111311221), we get a palindrome (2352242422532).

The spelling of 1221131111311 in words is "one trillion, two hundred twenty-one billion, one hundred thirty-one million, one hundred eleven thousand, three hundred eleven".