18817943 has 2 divisors, whose sum is σ = 18817944. Its totient is φ = 18817942.

The previous prime is 18817937. The next prime is 18817973. The reversal of 18817943 is 34971881.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18817943 is a prime.

It is a super-2 number, since 2×18817943² = 708229957502498, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18817943.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18817973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9408971 + 9408972.

It is an arithmetic number, because the mean of its divisors is an integer number (9408972).

Almost surely, 2^18817943 is an apocalyptic number.

18817943 is a deficient number, since it is larger than the sum of its proper divisors (1).

18817943 is an equidigital number, since it uses as much as digits as its factorization.

18817943 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48384, while the sum is 41.

The square root of 18817943 is about 4337.9653064542. The cubic root of 18817943 is about 265.9851453065.

The spelling of 18817943 in words is "eighteen million, eight hundred seventeen thousand, nine hundred forty-three".