1221211221220 has 24 divisors (see below), whose sum is σ = 2564822736000. Its totient is φ = 488431312992.

The previous prime is 1221211221211. The next prime is 1221211221239. The reversal of 1221211221220 is 221221121221.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3134890 + ... + 3502849.

It is an arithmetic number, because the mean of its divisors is an integer number (106867614000).

Almost surely, 2^{1221211221220} is an apocalyptic number.

1221211221220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221211221220 is an abundant number, since it is smaller than the sum of its proper divisors (1343611514780).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1221211221220 is a wasteful number, since it uses less digits than its factorization.

1221211221220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6646947 (or 6646945 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 1221211221220 its reverse (221221121221), we get a palindrome (1442432342441).

Subtracting from 1221211221220 its reverse (221221121221), we obtain a palindrome (999990099999).

The spelling of 1221211221220 in words is "one trillion, two hundred twenty-one billion, two hundred eleven million, two hundred twenty-one thousand, two hundred twenty".