12561000000 has 392 divisors, whose sum is σ = 42861951360. Its totient is φ = 3244800000.

The previous prime is 12560999987. The next prime is 12561000041. The reversal of 12561000000 is 16521.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 158999961 + ... + 159000039.

Almost surely, 2^12561000000 is an apocalyptic number.

12561000000 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 12561000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21430975680).

12561000000 is an abundant number, since it is smaller than the sum of its proper divisors (30300951360).

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

12561000000 is an frugal number, since it uses more digits than its factorization.

12561000000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 177 (or 142 counting only the distinct ones).

The product of its (nonzero) digits is 60, while the sum is 15.

Adding to 12561000000 its reverse (16521), we get a palindrome (12561016521).

The spelling of 12561000000 in words is "twelve billion, five hundred sixty-one million", and thus it is an aban number.