985809989 has 2 divisors, whose sum is σ = 985809990. Its totient is φ = 985809988.

The previous prime is 985809983. The next prime is 985810073. The reversal of 985809989 is 989908589.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 922336900 + 63473089 = 30370^2 + 7967^2 .

It is a cyclic number.

It is not a de Polignac number, because 985809989 - 2⁴ = 985809973 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (985809983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 492904994 + 492904995.

It is an arithmetic number, because the mean of its divisors is an integer number (492904995).

Almost surely, 2^985809989 is an apocalyptic number.

It is an amenable number.

985809989 is a deficient number, since it is larger than the sum of its proper divisors (1).

985809989 is an equidigital number, since it uses as much as digits as its factorization.

985809989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16796160, while the sum is 65.

The square root of 985809989 is about 31397.6111989431. The cubic root of 985809989 is about 995.2474453392.

The spelling of 985809989 in words is "nine hundred eighty-five million, eight hundred nine thousand, nine hundred eighty-nine".