635643 has 6 divisors (see below), whose sum is σ = 918164. Its totient is φ = 423756.

The previous prime is 635639. The next prime is 635653. The reversal of 635643 is 346536.

It is not a de Polignac number, because 635643 - 2² = 635639 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (635603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 35305 + ... + 35322.

2⁶³⁵⁶⁴³ is an apocalyptic number.

635643 is a deficient number, since it is larger than the sum of its proper divisors (282521).

635643 is a wasteful number, since it uses less digits than its factorization.

635643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70633 (or 70630 counting only the distinct ones).

The product of its digits is 6480, while the sum is 27.

The square root of 635643 is about 797.2722245256. The cubic root of 635643 is about 85.9813823048.

The spelling of 635643 in words is "six hundred thirty-five thousand, six hundred forty-three".