19998943 has 2 divisors, whose sum is σ = 19998944. Its totient is φ = 19998942.

The previous prime is 19998917. The next prime is 19998949. The reversal of 19998943 is 34989991.

It is a strong prime.

It is an emirp because it is prime and its reverse (34989991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19998943 - 2²¹ = 17901791 is a prime.

It is a super-2 number, since 2×19998943² = 799915442234498, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19998949) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9999471 + 9999472.

It is an arithmetic number, because the mean of its divisors is an integer number (9999472).

Almost surely, 2^19998943 is an apocalyptic number.

19998943 is a deficient number, since it is larger than the sum of its proper divisors (1).

19998943 is an equidigital number, since it uses as much as digits as its factorization.

19998943 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 629856, while the sum is 52.

The square root of 19998943 is about 4472.0177772455. The cubic root of 19998943 is about 271.4369796762.

The spelling of 19998943 in words is "nineteen million, nine hundred ninety-eight thousand, nine hundred forty-three".