1221100111011 has 24 divisors (see below), whose sum is σ = 1825447022784. Its totient is φ = 720059006880.

The previous prime is 1221100111003. The next prime is 1221100111051. The reversal of 1221100111011 is 1101110011221.

It is not a de Polignac number, because 1221100111011 - 2³ = 1221100111003 is a prime.

It is a super-2 number, since 2×1221100111011² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1221100111001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13469445 + ... + 13559798.

It is an arithmetic number, because the mean of its divisors is an integer number (76060292616).

Almost surely, 2^{1221100111011} is an apocalyptic number.

1221100111011 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1221100111011 is a deficient number, since it is larger than the sum of its proper divisors (604346911773).

1221100111011 is a wasteful number, since it uses less digits than its factorization.

1221100111011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27029331 (or 27029294 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 12.

Adding to 1221100111011 its reverse (1101110011221), we get a palindrome (2322210122232).

The spelling of 1221100111011 in words is "one trillion, two hundred twenty-one billion, one hundred million, one hundred eleven thousand, eleven".