19993943 has 2 divisors, whose sum is σ = 19993944. Its totient is φ = 19993942.

The previous prime is 19993927. The next prime is 19993951. The reversal of 19993943 is 34939991.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 19993943 - 2⁴ = 19993927 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19993903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9996971 + 9996972.

It is an arithmetic number, because the mean of its divisors is an integer number (9996972).

Almost surely, 2^19993943 is an apocalyptic number.

19993943 is a deficient number, since it is larger than the sum of its proper divisors (1).

19993943 is an equidigital number, since it uses as much as digits as its factorization.

19993943 is an evil number, because the sum of its binary digits is even.

The product of its digits is 236196, while the sum is 47.

The square root of 19993943 is about 4471.4587105328. The cubic root of 19993943 is about 271.4143568469.

The spelling of 19993943 in words is "nineteen million, nine hundred ninety-three thousand, nine hundred forty-three".