19985881 has 4 divisors (see below), whose sum is σ = 20034000. Its totient is φ = 19937764.

The previous prime is 19985869. The next prime is 19985909. The reversal of 19985881 is 18858991.

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 19985881 - 2¹¹ = 19983833 is a prime.

It is a super-2 number, since 2×19985881² = 798870878692322, which contains 22 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19985821) 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, 23431 + ... + 24268.

It is an arithmetic number, because the mean of its divisors is an integer number (5008500).

Almost surely, 2^19985881 is an apocalyptic number.

It is an amenable number.

19985881 is a deficient number, since it is larger than the sum of its proper divisors (48119).

19985881 is an equidigital number, since it uses as much as digits as its factorization.

19985881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48118.

The product of its digits is 207360, while the sum is 49.

The square root of 19985881 is about 4470.5571241178. The cubic root of 19985881 is about 271.3778718522.

The spelling of 19985881 in words is "nineteen million, nine hundred eighty-five thousand, eight hundred eighty-one".