1644169728 has 40 divisors (see below), whose sum is σ = 4380175008. Its totient is φ = 548056064.

The previous prime is 1644169717. The next prime is 1644169759. The reversal of 1644169728 is 8279614461.

It is a super-3 number, since 3×1644169728³ (a number of 29 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 533676 + ... + 536747.

Almost surely, 2^1644169728 is an apocalyptic number.

It is an amenable number.

1644169728 is an abundant number, since it is smaller than the sum of its proper divisors (2736005280).

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

1644169728 is an equidigital number, since it uses as much as digits as its factorization.

1644169728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1070444 (or 1070428 counting only the distinct ones).

The product of its digits is 580608, while the sum is 48.

The square root of 1644169728 is about 40548.3628276161. The cubic root of 1644169728 is about 1180.2723033352.

The spelling of 1644169728 in words is "one billion, six hundred forty-four million, one hundred sixty-nine thousand, seven hundred twenty-eight".