39509 has 2 divisors, whose sum is σ = 39510. Its totient is φ = 39508.

The previous prime is 39503. The next prime is 39511. The reversal of 39509 is 90593.

39509 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28900 + 10609 = 170^2 + 103^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-39509 is a prime.

It is a super-2 number, since 2×39509² = 3121922162, which contains 22 as substring.

Together with 39511, it forms a pair of twin primes.

It is a Chen prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (39503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19754 + 19755.

It is an arithmetic number, because the mean of its divisors is an integer number (19755).

2³⁹⁵⁰⁹ is an apocalyptic number.

It is an amenable number.

39509 is a deficient number, since it is larger than the sum of its proper divisors (1).

39509 is an equidigital number, since it uses as much as digits as its factorization.

39509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1215, while the sum is 26.

The square root of 39509 is about 198.7687098112. The cubic root of 39509 is about 34.0590094058.

The spelling of 39509 in words is "thirty-nine thousand, five hundred nine".