12561449736 has 384 divisors, whose sum is σ = 38704988160. Its totient is φ = 3363225600.

The previous prime is 12561449639. The next prime is 12561449779. The reversal of 12561449736 is 63794416521.

Its product of digits (1088640) is a multiple of the sum of its prime divisors (224).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 111163216 + ... + 111163328.

It is an arithmetic number, because the mean of its divisors is an integer number (100794240).

Almost surely, 2^12561449736 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 12561449736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (19352494080).

12561449736 is an abundant number, since it is smaller than the sum of its proper divisors (26143538424).

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

12561449736 is a wasteful number, since it uses less digits than its factorization.

12561449736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 245 (or 224 counting only the distinct ones).

The product of its digits is 1088640, while the sum is 48.

The spelling of 12561449736 in words is "twelve billion, five hundred sixty-one million, four hundred forty-nine thousand, seven hundred thirty-six".