18719893 has 2 divisors, whose sum is σ = 18719894. Its totient is φ = 18719892.

The previous prime is 18719887. The next prime is 18719917. The reversal of 18719893 is 39891781.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18301284 + 418609 = 4278^2 + 647^2 .

It is an emirp because it is prime and its reverse (39891781) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18719893 - 2²¹ = 16622741 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18719293) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9359946 + 9359947.

It is an arithmetic number, because the mean of its divisors is an integer number (9359947).

Almost surely, 2^18719893 is an apocalyptic number.

It is an amenable number.

18719893 is a deficient number, since it is larger than the sum of its proper divisors (1).

18719893 is an equidigital number, since it uses as much as digits as its factorization.

18719893 is an evil number, because the sum of its binary digits is even.

The product of its digits is 108864, while the sum is 46.

The square root of 18719893 is about 4326.6491653472. The cubic root of 18719893 is about 265.5223729584.

The spelling of 18719893 in words is "eighteen million, seven hundred nineteen thousand, eight hundred ninety-three".