19685689 has 4 divisors (see below), whose sum is σ = 19759140. Its totient is φ = 19612240.

The previous prime is 19685683. The next prime is 19685707. The reversal of 19685689 is 98658691.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 98658691 = 7451 ⋅13241.

It can be written as a sum of positive squares in 2 ways, for example, as 2941225 + 16744464 = 1715^2 + 4092^2 .

It is a cyclic number.

It is not a de Polignac number, because 19685689 - 2¹⁵ = 19652921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19685683) 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, 36322 + ... + 36859.

It is an arithmetic number, because the mean of its divisors is an integer number (4939785).

Almost surely, 2^19685689 is an apocalyptic number.

It is an amenable number.

19685689 is a deficient number, since it is larger than the sum of its proper divisors (73451).

19685689 is an equidigital number, since it uses as much as digits as its factorization.

19685689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73450.

The product of its digits is 933120, while the sum is 52.

The square root of 19685689 is about 4436.8557560507. The cubic root of 19685689 is about 270.0122948219.

The spelling of 19685689 in words is "nineteen million, six hundred eighty-five thousand, six hundred eighty-nine".