1644729984 has 192 divisors, whose sum is σ = 5023418400. Its totient is φ = 515082240.

The previous prime is 1644729979. The next prime is 1644730039. The reversal of 1644729984 is 4899274461.

1644729984 is a `hidden beast` number, since 1 + 6 + 4 + 472 + 99 + 84 = 666.

It is a tau number, because it is divible by the number of its divisors (192).

Its product of digits (3483648) is a multiple of the sum of its prime divisors (648).

It is a self number, because there is not a number n which added to its sum of digits gives 1644729984.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3567514 + ... + 3567974.

Almost surely, 2^1644729984 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1644729984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2511709200).

1644729984 is an abundant number, since it is smaller than the sum of its proper divisors (3378688416).

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

1644729984 is a wasteful number, since it uses less digits than its factorization.

1644729984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 663 (or 648 counting only the distinct ones).

The product of its digits is 3483648, while the sum is 54.

The square root of 1644729984 is about 40555.2707302023. The cubic root of 1644729984 is about 1180.4063486093.

The spelling of 1644729984 in words is "one billion, six hundred forty-four million, seven hundred twenty-nine thousand, nine hundred eighty-four".