1221100011121 has 4 divisors (see below), whose sum is σ = 1225445563044. Its totient is φ = 1216754459200.

The previous prime is 1221100011107. The next prime is 1221100011133. The reversal of 1221100011121 is 1211100011221.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 355388861025 + 865711150096 = 596145^2 + 930436^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221100011121 - 2⁷ = 1221100010993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221100011721) 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, 2172775540 + ... + 2172776101.

It is an arithmetic number, because the mean of its divisors is an integer number (306361390761).

Almost surely, 2^{1221100011121} is an apocalyptic number.

It is an amenable number.

1221100011121 is a deficient number, since it is larger than the sum of its proper divisors (4345551923).

1221100011121 is an equidigital number, since it uses as much as digits as its factorization.

1221100011121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4345551922.

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

Adding to 1221100011121 its reverse (1211100011221), we get a palindrome (2432200022342).

The spelling of 1221100011121 in words is "one trillion, two hundred twenty-one billion, one hundred million, eleven thousand, one hundred twenty-one".