1221330011220 has 384 divisors, whose sum is σ = 4196181749760. Its totient is φ = 292455360000.

The previous prime is 1221330011203. The next prime is 1221330011329. The reversal of 1221330011220 is 221100331221.

1221330011220 is a `hidden beast` number, since 1 + 221 + 330 + 0 + 112 + 2 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 1221330011193 and 1221330011202.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 162342379 + ... + 162349901.

It is an arithmetic number, because the mean of its divisors is an integer number (10927556640).

Almost surely, 2^{1221330011220} is an apocalyptic number.

1221330011220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221330011220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2098090874880).

1221330011220 is an abundant number, since it is smaller than the sum of its proper divisors (2974851738540).

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

1221330011220 is a wasteful number, since it uses less digits than its factorization.

1221330011220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7884 (or 7876 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 1221330011220 its reverse (221100331221), we get a palindrome (1442430342441).

The spelling of 1221330011220 in words is "one trillion, two hundred twenty-one billion, three hundred thirty million, eleven thousand, two hundred twenty".