635689 has 2 divisors, whose sum is σ = 635690. Its totient is φ = 635688.

The previous prime is 635659. The next prime is 635707. The reversal of 635689 is 986536.

635689 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., 469225 + 166464 = 685^2 + 408^2 .

It is a cyclic number.

It is not a de Polignac number, because 635689 - 2¹⁷ = 504617 is a prime.

It is a nialpdrome in base 15.

It is not a weakly prime, because it can be changed into another prime (635639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 317844 + 317845.

It is an arithmetic number, because the mean of its divisors is an integer number (317845).

2⁶³⁵⁶⁸⁹ is an apocalyptic number.

It is an amenable number.

635689 is a deficient number, since it is larger than the sum of its proper divisors (1).

635689 is an equidigital number, since it uses as much as digits as its factorization.

635689 is an evil number, because the sum of its binary digits is even.

The product of its digits is 38880, while the sum is 37.

The square root of 635689 is about 797.3010723685. The cubic root of 635689 is about 85.9834563454.

The spelling of 635689 in words is "six hundred thirty-five thousand, six hundred eighty-nine".