19887117 has 4 divisors (see below), whose sum is σ = 26516160. Its totient is φ = 13258076.

The previous prime is 19887097. The next prime is 19887121. The reversal of 19887117 is 71178891.

It is a happy number.

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 19887117 - 2¹⁰ = 19886093 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19887017) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3314517 + ... + 3314522.

It is an arithmetic number, because the mean of its divisors is an integer number (6629040).

Almost surely, 2^19887117 is an apocalyptic number.

It is an amenable number.

19887117 is a deficient number, since it is larger than the sum of its proper divisors (6629043).

19887117 is an equidigital number, since it uses as much as digits as its factorization.

19887117 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6629042.

The product of its digits is 28224, while the sum is 42.

The square root of 19887117 is about 4459.4973932048. The cubic root of 19887117 is about 270.9301118329.

The spelling of 19887117 in words is "nineteen million, eight hundred eighty-seven thousand, one hundred seventeen".