1221202112121 has 48 divisors (see below), whose sum is σ = 1797959159568. Its totient is φ = 798626304000.

The previous prime is 1221202112063. The next prime is 1221202112159. The reversal of 1221202112121 is 1212112021221.

1221202112121 is a `hidden beast` number, since 1 + 221 + 20 + 211 + 212 + 1 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 291017091600 + 930185020521 = 539460^2 + 964461^2 .

It is not a de Polignac number, because 1221202112121 - 2¹⁷ = 1221201981049 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1221202112094 and 1221202112103.

It is not an unprimeable number, because it can be changed into a prime (1221202112191) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 43142445 + ... + 43170741.

It is an arithmetic number, because the mean of its divisors is an integer number (37457482491).

Almost surely, 2^{1221202112121} is an apocalyptic number.

It is an amenable number.

1221202112121 is a deficient number, since it is larger than the sum of its proper divisors (576757047447).

1221202112121 is a wasteful number, since it uses less digits than its factorization.

1221202112121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28842 (or 28839 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 1221202112121 its reverse (1212112021221), we get a palindrome (2433314133342).

The spelling of 1221202112121 in words is "one trillion, two hundred twenty-one billion, two hundred two million, one hundred twelve thousand, one hundred twenty-one".