19985839 has 4 divisors (see below), whose sum is σ = 20096440. Its totient is φ = 19875240.

The previous prime is 19985831. The next prime is 19985869. The reversal of 19985839 is 93858991.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 19985839 - 2³ = 19985831 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19985831) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55029 + ... + 55390.

It is an arithmetic number, because the mean of its divisors is an integer number (5024110).

Almost surely, 2^19985839 is an apocalyptic number.

19985839 is a deficient number, since it is larger than the sum of its proper divisors (110601).

19985839 is a wasteful number, since it uses less digits than its factorization.

19985839 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110600.

The product of its digits is 699840, while the sum is 52.

The square root of 19985839 is about 4470.5524267142. The cubic root of 19985839 is about 271.3776817534.

The spelling of 19985839 in words is "nineteen million, nine hundred eighty-five thousand, eight hundred thirty-nine".