221121221222220 has 192 divisors, whose sum is σ = 685615445770752. Its totient is φ = 52796620800000.

The previous prime is 221121221222219. The next prime is 221121221222221. The reversal of 221121221222220 is 22222122121122.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (221121221222219) and next prime (221121221222221).

It is not an unprimeable number, because it can be changed into a prime (221121221222221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 278233420 + ... + 279027020.

It is an arithmetic number, because the mean of its divisors is an integer number (3570913780056).

Almost surely, 2^{221121221222220} is an apocalyptic number.

221121221222220 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 221121221222220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (342807722885376).

221121221222220 is an abundant number, since it is smaller than the sum of its proper divisors (464494224548532).

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

221121221222220 is a wasteful number, since it uses less digits than its factorization.

221121221222220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 799992 (or 799990 counting only the distinct ones).

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

Adding to 221121221222220 its reverse (22222122121122), we get a palindrome (243343343343342).

It can be divided in two parts, 2211212 and 21222220, that added together give a palindrome (23433432).

The spelling of 221121221222220 in words is "two hundred twenty-one trillion, one hundred twenty-one billion, two hundred twenty-one million, two hundred twenty-two thousand, two hundred twenty".