1221022221200 has 120 divisors (see below), whose sum is σ = 2985374984040. Its totient is φ = 479843020800.

The previous prime is 1221022221179. The next prime is 1221022221233. The reversal of 1221022221200 is 21222201221.

It is a happy number.

It can be written as a sum of positive squares in 12 ways, for example, as 1059318509824 + 161703711376 = 1029232^2 + 402124^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5479970 + ... + 5698430.

It is an arithmetic number, because the mean of its divisors is an integer number (24878124867).

Almost surely, 2^{1221022221200} is an apocalyptic number.

1221022221200 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 1221022221200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1492687492020).

1221022221200 is an abundant number, since it is smaller than the sum of its proper divisors (1764352762840).

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

1221022221200 is a wasteful number, since it uses less digits than its factorization.

1221022221200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 218725 (or 218714 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 1221022221200 its reverse (21222201221), we get a palindrome (1242244422421).

The spelling of 1221022221200 in words is "one trillion, two hundred twenty-one billion, twenty-two million, two hundred twenty-one thousand, two hundred".