19189985 has 4 divisors (see below), whose sum is σ = 23027988. Its totient is φ = 15351984.

The previous prime is 19189979. The next prime is 19189987. The reversal of 19189985 is 58998191.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58998191 = 7 ⋅8428313.

It can be written as a sum of positive squares in 2 ways, for example, as 14190289 + 4999696 = 3767^2 + 2236^2 .

It is a cyclic number.

It is not a de Polignac number, because 19189985 - 2¹⁴ = 19173601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19189987) 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, 1918994 + ... + 1919003.

It is an arithmetic number, because the mean of its divisors is an integer number (5756997).

Almost surely, 2^19189985 is an apocalyptic number.

It is an amenable number.

19189985 is a deficient number, since it is larger than the sum of its proper divisors (3838003).

19189985 is an equidigital number, since it uses as much as digits as its factorization.

19189985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3838002.

The product of its digits is 233280, while the sum is 50.

The square root of 19189985 is about 4380.6375106827. The cubic root of 19189985 is about 267.7266138035.

The spelling of 19189985 in words is "nineteen million, one hundred eighty-nine thousand, nine hundred eighty-five".