18519913 has 2 divisors, whose sum is σ = 18519914. Its totient is φ = 18519912.

The previous prime is 18519911. The next prime is 18519937. The reversal of 18519913 is 31991581.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14160169 + 4359744 = 3763^2 + 2088^2 .

It is an emirp because it is prime and its reverse (31991581) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18519913 - 2¹ = 18519911 is a prime.

Together with 18519911, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (18519911) 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 as a sum of consecutive naturals, namely, 9259956 + 9259957.

It is an arithmetic number, because the mean of its divisors is an integer number (9259957).

Almost surely, 2^18519913 is an apocalyptic number.

It is an amenable number.

18519913 is a deficient number, since it is larger than the sum of its proper divisors (1).

18519913 is an equidigital number, since it uses as much as digits as its factorization.

18519913 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9720, while the sum is 37.

The square root of 18519913 is about 4303.4768501759. The cubic root of 18519913 is about 264.5734826321.

The spelling of 18519913 in words is "eighteen million, five hundred nineteen thousand, nine hundred thirteen".