39989 has 2 divisors, whose sum is σ = 39990.
Its totient is φ = 39988.
The previous prime is 39983. The next prime is 40009. The reversal of 39989 is 98993.
39989 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
It is a weak prime.
It can be written as a sum of positive squares in only one way, i.e., 27889 + 12100 = 167^2 + 110^2
It is an emirp because it is prime and its reverse (98993) is a distict prime.
It is a cyclic number.
It is not a de Polignac number, because 39989 - 28 = 39733 is a prime.
It is a Sophie Germain 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 (39983) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19994 + 19995.
It is an arithmetic number, because the mean of its divisors is an integer number (19995).
239989 is an apocalyptic number.
It is an amenable number.
39989 is a deficient number, since it is larger than the sum of its proper divisors (1).
39989 is an equidigital number, since it uses as much as digits as its factorization.
39989 is an evil number, because the sum of its binary digits is even.
The product of its digits is 17496, while the sum is 38.
The square root of 39989 is about 199.9724981091.
The cubic root of 39989 is about 34.1963836902.
It can be divided in two parts, 399 and 89, that multiplied together give a triangular number (35511 = T266).
The spelling of 39989 in words is "thirty-nine thousand, nine hundred eighty-nine".