1221200121 has 12 divisors (see below), whose sum is σ = 1686353552. Its totient is φ = 786058224.

The previous prime is 1221200119. The next prime is 1221200159. The reversal of 1221200121 is 1210021221.

It is not a de Polignac number, because 1221200121 - 2¹ = 1221200119 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221200097 and 1221200106.

It is not an unprimeable number, because it can be changed into a prime (1221200161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 239491 + ... + 244536.

Almost surely, 2^1221200121 is an apocalyptic number.

It is an amenable number.

1221200121 is a deficient number, since it is larger than the sum of its proper divisors (465153431).

1221200121 is an equidigital number, since it uses as much as digits as its factorization.

1221200121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 484088 (or 484059 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 1221200121 is about 34945.6738524241. The cubic root of 1221200121 is about 1068.8799882658.

Adding to 1221200121 its reverse (1210021221), we get a palindrome (2431221342).

The spelling of 1221200121 in words is "one billion, two hundred twenty-one million, two hundred thousand, one hundred twenty-one".