18819913 has 4 divisors (see below), whose sum is σ = 21508480. Its totient is φ = 16131348.

The previous prime is 18819893. The next prime is 18819917. The reversal of 18819913 is 31991881.

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, and also an emirpimes, since its reverse is a distinct semiprime: 31991881 = 5479 ⋅5839.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18819913 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18819917) 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, 1344273 + ... + 1344286.

It is an arithmetic number, because the mean of its divisors is an integer number (5377120).

Almost surely, 2^18819913 is an apocalyptic number.

It is an amenable number.

18819913 is a deficient number, since it is larger than the sum of its proper divisors (2688567).

18819913 is an equidigital number, since it uses as much as digits as its factorization.

18819913 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2688566.

The product of its digits is 15552, while the sum is 40.

The square root of 18819913 is about 4338.1923654905. The cubic root of 18819913 is about 265.9944267398.

The spelling of 18819913 in words is "eighteen million, eight hundred nineteen thousand, nine hundred thirteen".