1221220212220 has 12 divisors (see below), whose sum is σ = 2564562445704. Its totient is φ = 488488084880.

The previous prime is 1221220212211. The next prime is 1221220212257. The reversal of 1221220212220 is 222120221221.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30530505286 + ... + 30530505325.

It is an arithmetic number, because the mean of its divisors is an integer number (213713537142).

Almost surely, 2^{1221220212220} is an apocalyptic number.

1221220212220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221220212220 is an abundant number, since it is smaller than the sum of its proper divisors (1343342233484).

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

1221220212220 is a wasteful number, since it uses less digits than its factorization.

1221220212220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61061010620 (or 61061010618 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 19.

Adding to 1221220212220 its reverse (222120221221), we get a palindrome (1443340433441).

Subtracting from 1221220212220 its reverse (222120221221), we obtain a palindrome (999099990999).

The spelling of 1221220212220 in words is "one trillion, two hundred twenty-one billion, two hundred twenty million, two hundred twelve thousand, two hundred twenty".