1221001110121 has 16 divisors (see below), whose sum is σ = 1426230641808. Its totient is φ = 1034906572800.

The previous prime is 1221001110113. The next prime is 1221001110139. The reversal of 1221001110121 is 1210111001221.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 425542256896 + 795458853225 = 652336^2 + 891885^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221001110121 - 2³ = 1221001110113 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221001110151) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 67367670 + ... + 67385791.

It is an arithmetic number, because the mean of its divisors is an integer number (89139415113).

Almost surely, 2^{1221001110121} is an apocalyptic number.

It is an amenable number.

1221001110121 is a deficient number, since it is larger than the sum of its proper divisors (205229531687).

1221001110121 is a wasteful number, since it uses less digits than its factorization.

1221001110121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134753532.

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

Adding to 1221001110121 its reverse (1210111001221), we get a palindrome (2431112111342).

The spelling of 1221001110121 in words is "one trillion, two hundred twenty-one billion, one million, one hundred ten thousand, one hundred twenty-one".