1221001011121 has 24 divisors (see below), whose sum is σ = 1280583444960. Its totient is φ = 1164013712640.

The previous prime is 1221001011107. The next prime is 1221001011143. The reversal of 1221001011121 is 1211101001221.

It is a happy number.

It is not a de Polignac number, because 1221001011121 - 2¹⁷ = 1221000880049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221001018121) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18372865 + ... + 18439201.

It is an arithmetic number, because the mean of its divisors is an integer number (53357643540).

Almost surely, 2^{1221001011121} is an apocalyptic number.

It is an amenable number.

1221001011121 is a deficient number, since it is larger than the sum of its proper divisors (59582433839).

1221001011121 is a wasteful number, since it uses less digits than its factorization.

1221001011121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66685 (or 66654 counting only the distinct ones).

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

Adding to 1221001011121 its reverse (1211101001221), we get a palindrome (2432102012342).

The spelling of 1221001011121 in words is "one trillion, two hundred twenty-one billion, one million, eleven thousand, one hundred twenty-one".