12661534551240 has 512 divisors, whose sum is σ = 43900061184000. Its totient is φ = 3243262353408.

The previous prime is 12661534551229. The next prime is 12661534551307. The reversal of 12661534551240 is 4215543516621.

12661534551240 is a `hidden beast` number, since 1 + 2 + 6 + 6 + 1 + 53 + 4 + 551 + 2 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 2692222729 + ... + 2692227431.

It is an arithmetic number, because the mean of its divisors is an integer number (85742307000).

Almost surely, 2^{12661534551240} is an apocalyptic number.

12661534551240 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 12661534551240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21950030592000).

12661534551240 is an abundant number, since it is smaller than the sum of its proper divisors (31238526632760).

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

12661534551240 is a wasteful number, since it uses less digits than its factorization.

12661534551240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5606 (or 5596 counting only the distinct ones).

The product of its (nonzero) digits is 864000, while the sum is 45.

The spelling of 12661534551240 in words is "twelve trillion, six hundred sixty-one billion, five hundred thirty-four million, five hundred fifty-one thousand, two hundred forty".