19439784021 has 16 divisors (see below), whose sum is σ = 29652451328. Its totient is φ = 11097226800.

The previous prime is 19439784011. The next prime is 19439784037. The reversal of 19439784021 is 12048793491.

It is not a de Polignac number, because 19439784021 - 2⁵ = 19439783989 is a prime.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19439784011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 446245 + ... + 487866.

It is an arithmetic number, because the mean of its divisors is an integer number (1853278208).

Almost surely, 2^19439784021 is an apocalyptic number.

It is an amenable number.

19439784021 is a deficient number, since it is larger than the sum of its proper divisors (10212667307).

19439784021 is an equidigital number, since it uses as much as digits as its factorization.

19439784021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 935112.

The product of its (nonzero) digits is 435456, while the sum is 48.

The spelling of 19439784021 in words is "nineteen billion, four hundred thirty-nine million, seven hundred eighty-four thousand, twenty-one".