12644189856 has 96 divisors (see below), whose sum is σ = 36910399680. Its totient is φ = 4211129088.

The previous prime is 12644189827. The next prime is 12644189867. The reversal of 12644189856 is 65898144621.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×12644189856² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1123650 + ... + 1134846.

It is an arithmetic number, because the mean of its divisors is an integer number (384483330).

Almost surely, 2^12644189856 is an apocalyptic number.

12644189856 is a gapful number since it is divisible by the number (16) 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 12644189856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18455199840).

12644189856 is an abundant number, since it is smaller than the sum of its proper divisors (24266209824).

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

12644189856 is a wasteful number, since it uses less digits than its factorization.

12644189856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12523 (or 12509 counting only the distinct ones).

The product of its digits is 3317760, while the sum is 54.

It can be divided in two parts, 12644 and 189856, that added together give a square (202500 = 450²).

The spelling of 12644189856 in words is "twelve billion, six hundred forty-four million, one hundred eighty-nine thousand, eight hundred fifty-six".