12121304420 has 72 divisors (see below), whose sum is σ = 26372038392. Its totient is φ = 4679700480.

The previous prime is 12121304413. The next prime is 12121304483. The reversal of 12121304420 is 2440312121.

It can be written as a sum of positive squares in 4 ways, for example, as 8637471844 + 3483832576 = 92938^2 + 59024^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 12121304392 and 12121304401.

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, 11089394 + ... + 11090486.

It is an arithmetic number, because the mean of its divisors is an integer number (366278311).

Almost surely, 2^12121304420 is an apocalyptic number.

12121304420 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 12121304420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13186019196).

12121304420 is an abundant number, since it is smaller than the sum of its proper divisors (14250733972).

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

12121304420 is a wasteful number, since it uses less digits than its factorization.

12121304420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1741 (or 1708 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

Adding to 12121304420 its reverse (2440312121), we get a palindrome (14561616541).

The spelling of 12121304420 in words is "twelve billion, one hundred twenty-one million, three hundred four thousand, four hundred twenty".