12121121220 has 192 divisors, whose sum is σ = 37525576704. Its totient is φ = 2904491520.

The previous prime is 12121121209. The next prime is 12121121273. The reversal of 12121121220 is 2212112121.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 12121121220.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 17541075 + ... + 17541765.

It is an arithmetic number, because the mean of its divisors is an integer number (195445712).

Almost surely, 2^12121121220 is an apocalyptic number.

12121121220 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 12121121220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18762788352).

12121121220 is an abundant number, since it is smaller than the sum of its proper divisors (25404455484).

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

12121121220 is a wasteful number, since it uses less digits than its factorization.

12121121220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1282 (or 1280 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 12121121220 its reverse (2212112121), we get a palindrome (14333233341).

Subtracting from 12121121220 its reverse (2212112121), we obtain a palindrome (9909009099).

The spelling of 12121121220 in words is "twelve billion, one hundred twenty-one million, one hundred twenty-one thousand, two hundred twenty".