19897393 has 4 divisors (see below), whose sum is σ = 20583540. Its totient is φ = 19211248.

The previous prime is 19897387. The next prime is 19897481. The reversal of 19897393 is 39379891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 39379891 = 2593 ⋅15187.

It can be written as a sum of positive squares in 2 ways, for example, as 13307904 + 6589489 = 3648^2 + 2567^2 .

It is a cyclic number.

It is not a de Polignac number, because 19897393 - 2¹⁷ = 19766321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19897333) 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, 343030 + ... + 343087.

It is an arithmetic number, because the mean of its divisors is an integer number (5145885).

Almost surely, 2^19897393 is an apocalyptic number.

It is an amenable number.

19897393 is a deficient number, since it is larger than the sum of its proper divisors (686147).

19897393 is an equidigital number, since it uses as much as digits as its factorization.

19897393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 686146.

The product of its digits is 367416, while the sum is 49.

The square root of 19897393 is about 4460.6493921850. The cubic root of 19897393 is about 270.9767684773.

The spelling of 19897393 in words is "nineteen million, eight hundred ninety-seven thousand, three hundred ninety-three".