20331989 has 2 divisors, whose sum is σ = 20331990. Its totient is φ = 20331988.

The previous prime is 20331967. The next prime is 20332043. The reversal of 20331989 is 98913302.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19731364 + 600625 = 4442^2 + 775^2 .

It is a cyclic number.

It is not a de Polignac number, because 20331989 - 2²⁰ = 19283413 is a prime.

It is a super-2 number, since 2×20331989² = 826779553392242, which contains 22 as substring.

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 (20331889) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10165994 + 10165995.

It is an arithmetic number, because the mean of its divisors is an integer number (10165995).

Almost surely, 2^20331989 is an apocalyptic number.

It is an amenable number.

20331989 is a deficient number, since it is larger than the sum of its proper divisors (1).

20331989 is an equidigital number, since it uses as much as digits as its factorization.

20331989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11664, while the sum is 35.

The square root of 20331989 is about 4509.1006863897. The cubic root of 20331989 is about 272.9354550500.

The spelling of 20331989 in words is "twenty million, three hundred thirty-one thousand, nine hundred eighty-nine".