20659889 has 2 divisors, whose sum is σ = 20659890. Its totient is φ = 20659888.

The previous prime is 20659871. The next prime is 20659901. The reversal of 20659889 is 98895602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14938225 + 5721664 = 3865^2 + 2392^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20659889 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (20659829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10329944 + 10329945.

It is an arithmetic number, because the mean of its divisors is an integer number (10329945).

Almost surely, 2^20659889 is an apocalyptic number.

It is an amenable number.

20659889 is a deficient number, since it is larger than the sum of its proper divisors (1).

20659889 is an equidigital number, since it uses as much as digits as its factorization.

20659889 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 311040, while the sum is 47.

The square root of 20659889 is about 4545.3150605871. The cubic root of 20659889 is about 274.3948743826.

The spelling of 20659889 in words is "twenty million, six hundred fifty-nine thousand, eight hundred eighty-nine".