18919213 has 2 divisors, whose sum is σ = 18919214. Its totient is φ = 18919212.

The previous prime is 18919189. The next prime is 18919237. The reversal of 18919213 is 31291981.

It is a balanced prime because it is at equal distance from previous prime (18919189) and next prime (18919237).

It can be written as a sum of positive squares in only one way, i.e., 11854249 + 7064964 = 3443^2 + 2658^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18919213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18919013) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9459606 + 9459607.

It is an arithmetic number, because the mean of its divisors is an integer number (9459607).

Almost surely, 2^18919213 is an apocalyptic number.

It is an amenable number.

18919213 is a deficient number, since it is larger than the sum of its proper divisors (1).

18919213 is an equidigital number, since it uses as much as digits as its factorization.

18919213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3888, while the sum is 34.

The square root of 18919213 is about 4349.6221674991. The cubic root of 18919213 is about 266.4614307992.

The spelling of 18919213 in words is "eighteen million, nine hundred nineteen thousand, two hundred thirteen".