12551561442 has 96 divisors (see below), whose sum is σ = 32492530560. Its totient is φ = 3518199360.

The previous prime is 12551561441. The next prime is 12551561447. The reversal of 12551561442 is 24416515521.

12551561442 is a `hidden beast` number, since 1 + 2 + 5 + 51 + 561 + 4 + 42 = 666.

It is a super-2 number, since 2×12551561442² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 12551561397 and 12551561406.

It is not an unprimeable number, because it can be changed into a prime (12551561441) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1055892 + ... + 1067712.

It is an arithmetic number, because the mean of its divisors is an integer number (338463860).

Almost surely, 2^12551561442 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 12551561442, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (16246265280).

12551561442 is an abundant number, since it is smaller than the sum of its proper divisors (19940969118).

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

12551561442 is a wasteful number, since it uses less digits than its factorization.

12551561442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11945 (or 11886 counting only the distinct ones).

The product of its digits is 48000, while the sum is 36.

The spelling of 12551561442 in words is "twelve billion, five hundred fifty-one million, five hundred sixty-one thousand, four hundred forty-two".