19821144 has 64 divisors (see below), whose sum is σ = 57139200. Its totient is φ = 5612544.

The previous prime is 19821127. The next prime is 19821173. The reversal of 19821144 is 44112891.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20872 + ... + 21800.

It is an arithmetic number, because the mean of its divisors is an integer number (892800).

Almost surely, 2^19821144 is an apocalyptic number.

19821144 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19821144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28569600).

19821144 is an abundant number, since it is smaller than the sum of its proper divisors (37318056).

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

19821144 is a wasteful number, since it uses less digits than its factorization.

19821144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1072 (or 1068 counting only the distinct ones).

The product of its digits is 2304, while the sum is 30.

The square root of 19821144 is about 4452.0943386231. The cubic root of 19821144 is about 270.6301877871.

The spelling of 19821144 in words is "nineteen million, eight hundred twenty-one thousand, one hundred forty-four".