21644355344612 has 288 divisors, whose sum is σ = 51476418572544. Its totient is φ = 7732504166400.

The previous prime is 21644355344611. The next prime is 21644355344617.

21644355344612 is nontrivially palindromic in base 10.

It is not an unprimeable number, because it can be changed into a prime (21644355344611) by changing a digit.

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 95 ways as a sum of consecutive naturals, for example, 10015896812 + ... + 10015898972.

It is an arithmetic number, because the mean of its divisors is an integer number (178737564488).

Almost surely, 2^{21644355344612} is an apocalyptic number.

21644355344612 is a gapful number since it is divisible by the number (22) 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 21644355344612, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25738209286272).

21644355344612 is an abundant number, since it is smaller than the sum of its proper divisors (29832063227932).

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

21644355344612 is a wasteful number, since it uses less digits than its factorization.

21644355344612 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3399 (or 3384 counting only the distinct ones).

The product of its digits is 8294400, while the sum is 50.

The spelling of 21644355344612 in words is "twenty-one trillion, six hundred forty-four billion, three hundred fifty-five million, three hundred forty-four thousand, six hundred twelve".