19980839 has 4 divisors (see below), whose sum is σ = 20221656. Its totient is φ = 19740024.

The previous prime is 19980823. The next prime is 19980869. The reversal of 19980839 is 93808991.

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 19980839 - 2⁴ = 19980823 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 19980793 and 19980802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19980809) 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 3 ways as a sum of consecutive naturals, for example, 120284 + ... + 120449.

It is an arithmetic number, because the mean of its divisors is an integer number (5055414).

Almost surely, 2^19980839 is an apocalyptic number.

19980839 is a deficient number, since it is larger than the sum of its proper divisors (240817).

19980839 is an equidigital number, since it uses as much as digits as its factorization.

19980839 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240816.

The product of its (nonzero) digits is 139968, while the sum is 47.

The square root of 19980839 is about 4469.9931767286. The cubic root of 19980839 is about 271.3550490353.

The spelling of 19980839 in words is "nineteen million, nine hundred eighty thousand, eight hundred thirty-nine".