19986491 has 4 divisors (see below), whose sum is σ = 22841712. Its totient is φ = 17131272.

The previous prime is 19986469. The next prime is 19986493. The reversal of 19986491 is 19468991.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 19986491 - 2¹⁰ = 19985467 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19986493) 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, 1427600 + ... + 1427613.

It is an arithmetic number, because the mean of its divisors is an integer number (5710428).

Almost surely, 2^19986491 is an apocalyptic number.

19986491 is a deficient number, since it is larger than the sum of its proper divisors (2855221).

19986491 is an equidigital number, since it uses as much as digits as its factorization.

19986491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2855220.

The product of its digits is 139968, while the sum is 47.

The square root of 19986491 is about 4470.6253477562. The cubic root of 19986491 is about 271.3806327816.

The spelling of 19986491 in words is "nineteen million, nine hundred eighty-six thousand, four hundred ninety-one".