12566636544 has 384 divisors, whose sum is σ = 42343741440. Its totient is φ = 3219456000.

The previous prime is 12566636539. The next prime is 12566636567. The reversal of 12566636544 is 44563666521.

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a junction number, because it is equal to n+sod(n) for n = 12566636493 and 12566636502.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 47781757 + ... + 47782019.

It is an arithmetic number, because the mean of its divisors is an integer number (110270160).

Almost surely, 2^12566636544 is an apocalyptic number.

12566636544 is a gapful number since it is divisible by the number (14) 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 12566636544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21171870720).

12566636544 is an abundant number, since it is smaller than the sum of its proper divisors (29777104896).

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

12566636544 is a wasteful number, since it uses less digits than its factorization.

12566636544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 407 (or 387 counting only the distinct ones).

The product of its digits is 3110400, while the sum is 48.

The spelling of 12566636544 in words is "twelve billion, five hundred sixty-six million, six hundred thirty-six thousand, five hundred forty-four".