19981393 has 4 divisors (see below), whose sum is σ = 19990528. Its totient is φ = 19972260.

The previous prime is 19981373. The next prime is 19981397. The reversal of 19981393 is 39318991.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 19981393 - 2⁵ = 19981361 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19981397) 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, 880 + ... + 6382.

It is an arithmetic number, because the mean of its divisors is an integer number (4997632).

Almost surely, 2^19981393 is an apocalyptic number.

It is an amenable number.

19981393 is a deficient number, since it is larger than the sum of its proper divisors (9135).

19981393 is an equidigital number, since it uses as much as digits as its factorization.

19981393 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9134.

The product of its digits is 52488, while the sum is 43.

The square root of 19981393 is about 4470.0551450737. The cubic root of 19981393 is about 271.3575569265.

The spelling of 19981393 in words is "nineteen million, nine hundred eighty-one thousand, three hundred ninety-three".