12123131220 has 96 divisors (see below), whose sum is σ = 37736240640. Its totient is φ = 3231135360.

The previous prime is 12123131213. The next prime is 12123131231. The reversal of 12123131220 is 2213132121.

12123131220 is a `hidden beast` number, since 121 + 231 + 312 + 2 + 0 = 666.

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 = 12123131193 and 12123131202.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1282110 + ... + 1291530.

It is an arithmetic number, because the mean of its divisors is an integer number (393085840).

Almost surely, 2^12123131220 is an apocalyptic number.

12123131220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

12123131220 is an abundant number, since it is smaller than the sum of its proper divisors (25613109420).

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

12123131220 is a wasteful number, since it uses less digits than its factorization.

12123131220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11822 (or 11814 counting only the distinct ones).

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

Adding to 12123131220 its reverse (2213132121), we get a palindrome (14336263341).

Subtracting from 12123131220 its reverse (2213132121), we obtain a palindrome (9909999099).

The spelling of 12123131220 in words is "twelve billion, one hundred twenty-three million, one hundred thirty-one thousand, two hundred twenty".