21644566544612 has 12 divisors (see below), whose sum is σ = 41321445221616. Its totient is φ = 9838439338440.

The previous prime is 21644566544551. The next prime is 21644566544639.

21644566544612 is nontrivially palindromic in base 10.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 245960983418 + ... + 245960983505.

It is an arithmetic number, because the mean of its divisors is an integer number (3443453768468).

Almost surely, 2^{21644566544612} is an apocalyptic number.

21644566544612 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21644566544612 is a deficient number, since it is larger than the sum of its proper divisors (19676878677004).

21644566544612 is a wasteful number, since it uses less digits than its factorization.

21644566544612 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 491921966938 (or 491921966936 counting only the distinct ones).

The product of its digits is 33177600, while the sum is 56.

The spelling of 21644566544612 in words is "twenty-one trillion, six hundred forty-four billion, five hundred sixty-six million, five hundred forty-four thousand, six hundred twelve".