1221100211011 has 4 divisors (see below), whose sum is σ = 1221102430552. Its totient is φ = 1221097991472.

The previous prime is 1221100210951. The next prime is 1221100211033. The reversal of 1221100211011 is 1101120011221.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 1221100211011 - 2²³ = 1221091822403 is a prime.

It is a super-2 number, since 2×1221100211011² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221100210982 and 1221100211000.

It is not an unprimeable number, because it can be changed into a prime (1221100214011) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 401260 + ... + 1613446.

It is an arithmetic number, because the mean of its divisors is an integer number (305275607638).

Almost surely, 2^{1221100211011} is an apocalyptic number.

1221100211011 is a deficient number, since it is larger than the sum of its proper divisors (2219541).

1221100211011 is a wasteful number, since it uses less digits than its factorization.

1221100211011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2219540.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 1221100211011 its reverse (1101120011221), we get a palindrome (2322220222232).

The spelling of 1221100211011 in words is "one trillion, two hundred twenty-one billion, one hundred million, two hundred eleven thousand, eleven".