1221211011220 has 48 divisors (see below), whose sum is σ = 2627236459008. Its totient is φ = 476544119040.

The previous prime is 1221211011199. The next prime is 1221211011227. The reversal of 1221211011220 is 221101121221.

It is a junction number, because it is equal to n+sod(n) for n = 1221211011194 and 1221211011203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221211011227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22788097 + ... + 22841623.

It is an arithmetic number, because the mean of its divisors is an integer number (54734092896).

Almost surely, 2^{1221211011220} is an apocalyptic number.

1221211011220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221211011220 is an abundant number, since it is smaller than the sum of its proper divisors (1406025447788).

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

1221211011220 is a wasteful number, since it uses less digits than its factorization.

1221211011220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81400 (or 81398 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 1221211011220 its reverse (221101121221), we get a palindrome (1442312132441).

The spelling of 1221211011220 in words is "one trillion, two hundred twenty-one billion, two hundred eleven million, eleven thousand, two hundred twenty".