1644444080 has 20 divisors (see below), whose sum is σ = 3823332672. Its totient is φ = 657777600.

The previous prime is 1644444077. The next prime is 1644444083. The reversal of 1644444080 is 804444461.

It is an interprime number because it is at equal distance from previous prime (1644444077) and next prime (1644444083).

It is a tau number, because it is divible by the number of its divisors (20).

It is a hoax number, since the sum of its digits (35) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 1644444080.

It is not an unprimeable number, because it can be changed into a prime (1644444083) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10277696 + ... + 10277855.

Almost surely, 2^1644444080 is an apocalyptic number.

1644444080 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1644444080 is an abundant number, since it is smaller than the sum of its proper divisors (2178888592).

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

1644444080 is a wasteful number, since it uses less digits than its factorization.

1644444080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20555564 (or 20555558 counting only the distinct ones).

The product of its (nonzero) digits is 49152, while the sum is 35.

The square root of 1644444080 is about 40551.7457084156. The cubic root of 1644444080 is about 1180.3379478269.

The spelling of 1644444080 in words is "one billion, six hundred forty-four million, four hundred forty-four thousand, eighty".