12420400520 has 64 divisors (see below), whose sum is σ = 30617533440. Its totient is φ = 4497088000.

The previous prime is 12420400501. The next prime is 12420400523. The reversal of 12420400520 is 2500402421.

It is a happy number.

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 = 12420400492 and 12420400501.

It is not an unprimeable number, because it can be changed into a prime (12420400523) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41945 + ... + 163095.

It is an arithmetic number, because the mean of its divisors is an integer number (478398960).

Almost surely, 2^12420400520 is an apocalyptic number.

12420400520 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 12420400520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15308766720).

12420400520 is an abundant number, since it is smaller than the sum of its proper divisors (18197132920).

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

12420400520 is a wasteful number, since it uses less digits than its factorization.

12420400520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121406 (or 121402 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 20.

Adding to 12420400520 its reverse (2500402421), we get a palindrome (14920802941).

The spelling of 12420400520 in words is "twelve billion, four hundred twenty million, four hundred thousand, five hundred twenty".