19985939 has 2 divisors, whose sum is σ = 19985940. Its totient is φ = 19985938.

The previous prime is 19985923. The next prime is 19985941. The reversal of 19985939 is 93958991.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 19985939 - 2⁴ = 19985923 is a prime.

Together with 19985941, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (19985909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9992969 + 9992970.

It is an arithmetic number, because the mean of its divisors is an integer number (9992970).

Almost surely, 2^19985939 is an apocalyptic number.

19985939 is a deficient number, since it is larger than the sum of its proper divisors (1).

19985939 is an equidigital number, since it uses as much as digits as its factorization.

19985939 is an evil number, because the sum of its binary digits is even.

The product of its digits is 787320, while the sum is 53.

The square root of 19985939 is about 4470.5636110003. The cubic root of 19985939 is about 271.3781343693.

The spelling of 19985939 in words is "nineteen million, nine hundred eighty-five thousand, nine hundred thirty-nine".