12128505840 has 400 divisors, whose sum is σ = 48661572960. Its totient is φ = 2767011840.

The previous prime is 12128505817. The next prime is 12128505841. The reversal of 12128505840 is 4850582121.

12128505840 is a `hidden beast` number, since 1 + 2 + 1 + 28 + 50 + 584 + 0 = 666.

It is a super-3 number, since 3×12128505840³ (a number of 31 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 12128505795 and 12128505804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12128505841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 1206756 + ... + 1216764.

Almost surely, 2^12128505840 is an apocalyptic number.

12128505840 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 12128505840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24330786480).

12128505840 is an abundant number, since it is smaller than the sum of its proper divisors (36533067120).

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

12128505840 is a wasteful number, since it uses less digits than its factorization.

12128505840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10062 (or 10047 counting only the distinct ones).

The product of its (nonzero) digits is 25600, while the sum is 36.

The spelling of 12128505840 in words is "twelve billion, one hundred twenty-eight million, five hundred five thousand, eight hundred forty".