20191984 has 40 divisors (see below), whose sum is σ = 41584640. Its totient is φ = 9471168.

The previous prime is 20191931. The next prime is 20191987. The reversal of 20191984 is 48919102.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20191987) 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 7 ways as a sum of consecutive naturals, for example, 38347 + ... + 38869.

It is an arithmetic number, because the mean of its divisors is an integer number (1039616).

Almost surely, 2^20191984 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 20191984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20792320).

20191984 is an abundant number, since it is smaller than the sum of its proper divisors (21392656).

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

20191984 is a wasteful number, since it uses less digits than its factorization.

20191984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 677 (or 671 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 34.

The square root of 20191984 is about 4493.5491540652. The cubic root of 20191984 is about 272.3075385384.

The spelling of 20191984 in words is "twenty million, one hundred ninety-one thousand, nine hundred eighty-four".