1221211121 has 8 divisors (see below), whose sum is σ = 1330996800. Its totient is φ = 1113689232.

The previous prime is 1221211067. The next prime is 1221211127. The reversal of 1221211121 is 1211121221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221211121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221211096 and 1221211105.

It is not an unprimeable number, because it can be changed into a prime (1221211127) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 564821 + ... + 566978.

It is an arithmetic number, because the mean of its divisors is an integer number (166374600).

Almost surely, 2^1221211121 is an apocalyptic number.

It is an amenable number.

1221211121 is a deficient number, since it is larger than the sum of its proper divisors (109785679).

1221211121 is a wasteful number, since it uses less digits than its factorization.

1221211121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1131895.

The product of its digits is 16, while the sum is 14.

The square root of 1221211121 is about 34945.8312392194. The cubic root of 1221211121 is about 1068.8831975800.

Adding to 1221211121 its reverse (1211121221), we get a palindrome (2432332342).

The spelling of 1221211121 in words is "one billion, two hundred twenty-one million, two hundred eleven thousand, one hundred twenty-one".