20319989 has 2 divisors, whose sum is σ = 20319990. Its totient is φ = 20319988.

The previous prime is 20319931. The next prime is 20320007. The reversal of 20319989 is 98991302.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20295025 + 24964 = 4505^2 + 158^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20319989 is a 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 (20319389) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10159994 + 10159995.

It is an arithmetic number, because the mean of its divisors is an integer number (10159995).

Almost surely, 2^20319989 is an apocalyptic number.

It is an amenable number.

20319989 is a deficient number, since it is larger than the sum of its proper divisors (1).

20319989 is an equidigital number, since it uses as much as digits as its factorization.

20319989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34992, while the sum is 41.

The square root of 20319989 is about 4507.7698477185. The cubic root of 20319989 is about 272.8817487120.

The spelling of 20319989 in words is "twenty million, three hundred nineteen thousand, nine hundred eighty-nine".