12891805406550 has 288 divisors, whose sum is σ = 40664588799744. Its totient is φ = 2866298400000.

The previous prime is 12891805406539. The next prime is 12891805406563. The reversal of 12891805406550 is 5560450819821.

12891805406550 is a `hidden beast` number, since 1 + 2 + 8 + 9 + 1 + 80 + 5 + 4 + 0 + 6 + 550 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 518751625 + ... + 518776475.

It is an arithmetic number, because the mean of its divisors is an integer number (141196488888).

Almost surely, 2^{12891805406550} is an apocalyptic number.

12891805406550 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 12891805406550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20332294399872).

12891805406550 is an abundant number, since it is smaller than the sum of its proper divisors (27772783393194).

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

12891805406550 is a wasteful number, since it uses less digits than its factorization.

12891805406550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29364 (or 29356 counting only the distinct ones).

The product of its (nonzero) digits is 3456000, while the sum is 54.

The spelling of 12891805406550 in words is "twelve trillion, eight hundred ninety-one billion, eight hundred five million, four hundred six thousand, five hundred fifty".