12556129920 has 128 divisors (see below), whose sum is σ = 40328988480. Its totient is φ = 3322675200.

The previous prime is 12556129813. The next prime is 12556129921. The reversal of 12556129920 is 2992165521.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (128).

It is not an unprimeable number, because it can be changed into a prime (12556129921) 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, 226560 + ... + 276480.

Almost surely, 2^12556129920 is an apocalyptic number.

12556129920 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 12556129920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20164494240).

12556129920 is an abundant number, since it is smaller than the sum of its proper divisors (27772858560).

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

12556129920 is a wasteful number, since it uses less digits than its factorization.

12556129920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50074 (or 50062 counting only the distinct ones).

The product of its (nonzero) digits is 97200, while the sum is 42.

The spelling of 12556129920 in words is "twelve billion, five hundred fifty-six million, one hundred twenty-nine thousand, nine hundred twenty".