19990043 has 2 divisors, whose sum is σ = 19990044. Its totient is φ = 19990042.

The previous prime is 19990031. The next prime is 19990049. The reversal of 19990043 is 34009991.

It is a strong prime.

It is an emirp because it is prime and its reverse (34009991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19990043 - 2²² = 15795739 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 19989985 and 19990012.

It is not a weakly prime, because it can be changed into another prime (19990049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9995021 + 9995022.

It is an arithmetic number, because the mean of its divisors is an integer number (9995022).

Almost surely, 2^19990043 is an apocalyptic number.

19990043 is a deficient number, since it is larger than the sum of its proper divisors (1).

19990043 is an equidigital number, since it uses as much as digits as its factorization.

19990043 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8748, while the sum is 35.

The square root of 19990043 is about 4471.0225899675. The cubic root of 19990043 is about 271.3967084217.

The spelling of 19990043 in words is "nineteen million, nine hundred ninety thousand, forty-three".