16644563680365 has 64 divisors (see below), whose sum is σ = 30884173332480. Its totient is φ = 8489131801920.

The previous prime is 16644563680361. The next prime is 16644563680379. The reversal of 16644563680365 is 56308636544661.

16644563680365 is a `hidden beast` number, since 1 + 6 + 6 + 4 + 4 + 563 + 6 + 8 + 0 + 3 + 65 = 666.

It is not a de Polignac number, because 16644563680365 - 2² = 16644563680361 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16644563680361) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 12542820 + ... + 13806210.

It is an arithmetic number, because the mean of its divisors is an integer number (482565208320).

Almost surely, 2^{16644563680365} is an apocalyptic number.

16644563680365 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

16644563680365 is a deficient number, since it is larger than the sum of its proper divisors (14239609652115).

16644563680365 is a wasteful number, since it uses less digits than its factorization.

16644563680365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1267671 (or 1267665 counting only the distinct ones).

The product of its (nonzero) digits is 223948800, while the sum is 63.

The spelling of 16644563680365 in words is "sixteen trillion, six hundred forty-four billion, five hundred sixty-three million, six hundred eighty thousand, three hundred sixty-five".