19985689 has 4 divisors (see below), whose sum is σ = 20854656. Its totient is φ = 19116724.

The previous prime is 19985687. The next prime is 19985711. The reversal of 19985689 is 98658991.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 19985689 - 2¹ = 19985687 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19985681) 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, 434449 + ... + 434494.

It is an arithmetic number, because the mean of its divisors is an integer number (5213664).

Almost surely, 2^19985689 is an apocalyptic number.

It is an amenable number.

19985689 is a deficient number, since it is larger than the sum of its proper divisors (868967).

19985689 is an equidigital number, since it uses as much as digits as its factorization.

19985689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 868966.

The product of its digits is 1399680, while the sum is 55.

The square root of 19985689 is about 4470.5356502325. The cubic root of 19985689 is about 271.3770028268.

The spelling of 19985689 in words is "nineteen million, nine hundred eighty-five thousand, six hundred eighty-nine".