19918313 has 2 divisors, whose sum is σ = 19918314. Its totient is φ = 19918312.

The previous prime is 19918303. The next prime is 19918319. The reversal of 19918313 is 31381991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15389929 + 4528384 = 3923^2 + 2128^2 .

It is an emirp because it is prime and its reverse (31381991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19918313 - 2⁸ = 19918057 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (19918319) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9959156 + 9959157.

It is an arithmetic number, because the mean of its divisors is an integer number (9959157).

Almost surely, 2^19918313 is an apocalyptic number.

It is an amenable number.

19918313 is a deficient number, since it is larger than the sum of its proper divisors (1).

19918313 is an equidigital number, since it uses as much as digits as its factorization.

19918313 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5832, while the sum is 35.

The square root of 19918313 is about 4462.9937261887. The cubic root of 19918313 is about 271.0717029985.

The spelling of 19918313 in words is "nineteen million, nine hundred eighteen thousand, three hundred thirteen".