19816493 has 4 divisors (see below), whose sum is σ = 19836960. Its totient is φ = 19796028.

The previous prime is 19816481. The next prime is 19816513. The reversal of 19816493 is 39461891.

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 19816493 - 2¹⁰ = 19815469 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 19816493.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19816453) 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, 8705 + ... + 10742.

It is an arithmetic number, because the mean of its divisors is an integer number (4959240).

Almost surely, 2^19816493 is an apocalyptic number.

It is an amenable number.

19816493 is a deficient number, since it is larger than the sum of its proper divisors (20467).

19816493 is a wasteful number, since it uses less digits than its factorization.

19816493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20466.

The product of its digits is 46656, while the sum is 41.

The square root of 19816493 is about 4451.5719695406. The cubic root of 19816493 is about 270.6090184832.

The spelling of 19816493 in words is "nineteen million, eight hundred sixteen thousand, four hundred ninety-three".