221221122221220 has 384 divisors, whose sum is σ = 689492356116480. Its totient is φ = 52546830336000.

The previous prime is 221221122221219. The next prime is 221221122221269. The reversal of 221221122221220 is 22122221122122.

It is a happy number.

It is an unprimeable number.

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 127 ways as a sum of consecutive naturals, for example, 15710604580 + ... + 15710618660.

It is an arithmetic number, because the mean of its divisors is an integer number (1795553010720).

Almost surely, 2^{221221122221220} is an apocalyptic number.

221221122221220 is a gapful number since it is divisible by the number (20) 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 221221122221220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (344746178058240).

221221122221220 is an abundant number, since it is smaller than the sum of its proper divisors (468271233895260).

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

221221122221220 is a wasteful number, since it uses less digits than its factorization.

221221122221220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16227 (or 16225 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 24.

Adding to 221221122221220 its reverse (22122221122122), we get a palindrome (243343343343342).

The spelling of 221221122221220 in words is "two hundred twenty-one trillion, two hundred twenty-one billion, one hundred twenty-two million, two hundred twenty-one thousand, two hundred twenty".