1221200222121 has 24 divisors (see below), whose sum is σ = 1926962541504. Its totient is φ = 739103254560.

The previous prime is 1221200222117. The next prime is 1221200222141. The reversal of 1221200222121 is 1212220021221.

It is a happy number.

1221200222121 is a `hidden beast` number, since 1 + 221 + 200 + 2 + 221 + 21 = 666.

It is not a de Polignac number, because 1221200222121 - 2² = 1221200222117 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221200222094 and 1221200222103.

It is not an unprimeable number, because it can be changed into a prime (1221200222101) 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, 8411766 + ... + 8555711.

It is an arithmetic number, because the mean of its divisors is an integer number (80290105896).

Almost surely, 2^{1221200222121} is an apocalyptic number.

1221200222121 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221200222121 is a deficient number, since it is larger than the sum of its proper divisors (705762319383).

1221200222121 is a wasteful number, since it uses less digits than its factorization.

1221200222121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16968221 (or 16968218 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 1221200222121 its reverse (1212220021221), we get a palindrome (2433420243342).

The spelling of 1221200222121 in words is "one trillion, two hundred twenty-one billion, two hundred million, two hundred twenty-two thousand, one hundred twenty-one".