19781328 has 80 divisors (see below), whose sum is σ = 59031936. Its totient is φ = 5591040.

The previous prime is 19781327. The next prime is 19781369. The reversal of 19781328 is 82318791.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19781323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37708 + ... + 38228.

Almost surely, 2^19781328 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 19781328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29515968).

19781328 is an abundant number, since it is smaller than the sum of its proper divisors (39250608).

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

19781328 is a wasteful number, since it uses less digits than its factorization.

19781328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 652 (or 646 counting only the distinct ones).

The product of its digits is 24192, while the sum is 39.

The square root of 19781328 is about 4447.6204874067. The cubic root of 19781328 is about 270.4488555911.

The spelling of 19781328 in words is "nineteen million, seven hundred eighty-one thousand, three hundred twenty-eight".