635989 has 2 divisors, whose sum is σ = 635990. Its totient is φ = 635988.

The previous prime is 635983. The next prime is 636017. The reversal of 635989 is 989536.

635989 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., 342225 + 293764 = 585^2 + 542^2 .

It is a cyclic number.

It is not a de Polignac number, because 635989 - 2³ = 635981 is a prime.

It is a Chen prime.

It is a plaindrome in base 14.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (635981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 317994 + 317995.

It is an arithmetic number, because the mean of its divisors is an integer number (317995).

2⁶³⁵⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

635989 is a deficient number, since it is larger than the sum of its proper divisors (1).

635989 is an equidigital number, since it uses as much as digits as its factorization.

635989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 58320, while the sum is 40.

The square root of 635989 is about 797.4891848796. The cubic root of 635989 is about 85.9969802437.

The spelling of 635989 in words is "six hundred thirty-five thousand, nine hundred eighty-nine".