19998743 has 2 divisors, whose sum is σ = 19998744. Its totient is φ = 19998742.

The previous prime is 19998733. The next prime is 19998757. The reversal of 19998743 is 34789991.

It is a weak prime.

It is an emirp because it is prime and its reverse (34789991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19998743 - 2⁶ = 19998679 is a prime.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 19998691 and 19998700.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19998733) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9999371 + 9999372.

It is an arithmetic number, because the mean of its divisors is an integer number (9999372).

Almost surely, 2^19998743 is an apocalyptic number.

19998743 is a deficient number, since it is larger than the sum of its proper divisors (1).

19998743 is an equidigital number, since it uses as much as digits as its factorization.

19998743 is an evil number, because the sum of its binary digits is even.

The product of its digits is 489888, while the sum is 50.

The square root of 19998743 is about 4471.9954159189. The cubic root of 19998743 is about 271.4360748354.

The spelling of 19998743 in words is "nineteen million, nine hundred ninety-eight thousand, seven hundred forty-three".