19659989 has 2 divisors, whose sum is σ = 19659990. Its totient is φ = 19659988.

The previous prime is 19659967. The next prime is 19660001. The reversal of 19659989 is 98995691.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17783089 + 1876900 = 4217^2 + 1370^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19659989 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19659929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9829994 + 9829995.

It is an arithmetic number, because the mean of its divisors is an integer number (9829995).

Almost surely, 2^19659989 is an apocalyptic number.

It is an amenable number.

19659989 is a deficient number, since it is larger than the sum of its proper divisors (1).

19659989 is an equidigital number, since it uses as much as digits as its factorization.

19659989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1574640, while the sum is 56.

The square root of 19659989 is about 4433.9586150527. The cubic root of 19659989 is about 269.8947417784.

The spelling of 19659989 in words is "nineteen million, six hundred fifty-nine thousand, nine hundred eighty-nine".