12121331220 has 36 divisors (see below), whose sum is σ = 36768038580. Its totient is φ = 3232354944.

The previous prime is 12121331207. The next prime is 12121331251. The reversal of 12121331220 is 2213312121.

12121331220 is a `hidden beast` number, since 121 + 213 + 312 + 20 = 666.

12121331220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 4720514436 + 7400816784 = 68706^2 + 86028^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 12121331193 and 12121331202.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 33670185 + ... + 33670544.

It is an arithmetic number, because the mean of its divisors is an integer number (1021334405).

Almost surely, 2^12121331220 is an apocalyptic number.

12121331220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

12121331220 is an abundant number, since it is smaller than the sum of its proper divisors (24646707360).

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

12121331220 is a wasteful number, since it uses less digits than its factorization.

12121331220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67340744 (or 67340739 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 12121331220 its reverse (2213312121), we get a palindrome (14334643341).

The spelling of 12121331220 in words is "twelve billion, one hundred twenty-one million, three hundred thirty-one thousand, two hundred twenty".