1221212210121 has 12 divisors (see below), whose sum is σ = 1764178203060. Its totient is φ = 814046853120.

The previous prime is 1221212210077. The next prime is 1221212210149. The reversal of 1221212210121 is 1210122121221.

1221212210121 is a `hidden beast` number, since 1 + 221 + 212 + 210 + 1 + 21 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 105677006400 + 1115535203721 = 325080^2 + 1056189^2 .

It is not a de Polignac number, because 1221212210121 - 2³⁴ = 1204032340937 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221212210094 and 1221212210103.

It is not an unprimeable number, because it can be changed into a prime (1221212210161) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7803240 + ... + 7958201.

It is an arithmetic number, because the mean of its divisors is an integer number (147014850255).

Almost surely, 2^{1221212210121} is an apocalyptic number.

It is an amenable number.

1221212210121 is a deficient number, since it is larger than the sum of its proper divisors (542965992939).

1221212210121 is a wasteful number, since it uses less digits than its factorization.

1221212210121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15770056 (or 15770053 counting only the distinct ones).

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

Adding to 1221212210121 its reverse (1210122121221), we get a palindrome (2431334331342).

The spelling of 1221212210121 in words is "one trillion, two hundred twenty-one billion, two hundred twelve million, two hundred ten thousand, one hundred twenty-one".