19981744 has 10 divisors (see below), whose sum is σ = 38714660. Its totient is φ = 9990864.

The previous prime is 19981727. The next prime is 19981757. The reversal of 19981744 is 44718991.

It is a self number, because there is not a number n which added to its sum of digits gives 19981744.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 624414 + ... + 624445.

It is an arithmetic number, because the mean of its divisors is an integer number (3871466).

Almost surely, 2^19981744 is an apocalyptic number.

It is an amenable number.

19981744 is a deficient number, since it is larger than the sum of its proper divisors (18732916).

19981744 is a wasteful number, since it uses less digits than its factorization.

19981744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1248867 (or 1248861 counting only the distinct ones).

The product of its digits is 72576, while the sum is 43.

The square root of 19981744 is about 4470.0944061619. The cubic root of 19981744 is about 271.3591458371.

The spelling of 19981744 in words is "nineteen million, nine hundred eighty-one thousand, seven hundred forty-four".