12121021220 has 144 divisors (see below), whose sum is σ = 32412768192. Its totient is φ = 3765000960.

The previous prime is 12121021201. The next prime is 12121021261. The reversal of 12121021220 is 2212012121.

It is a Harshad number since it is a multiple of its sum of digits (14).

It is a junction number, because it is equal to n+sod(n) for n = 12121021195 and 12121021204.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3415487 + ... + 3419033.

It is an arithmetic number, because the mean of its divisors is an integer number (225088668).

Almost surely, 2^12121021220 is an apocalyptic number.

12121021220 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 12121021220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (16206384096).

12121021220 is an abundant number, since it is smaller than the sum of its proper divisors (20291746972).

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

12121021220 is a wasteful number, since it uses less digits than its factorization.

12121021220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3898 (or 3889 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 12121021220 its reverse (2212012121), we get a palindrome (14333033341).

Subtracting from 12121021220 its reverse (2212012121), we obtain a palindrome (9909009099).

The spelling of 12121021220 in words is "twelve billion, one hundred twenty-one million, twenty-one thousand, two hundred twenty".