636505 has 4 divisors (see below), whose sum is σ = 763812. Its totient is φ = 509200.

The previous prime is 636499. The next prime is 636533. The reversal of 636505 is 505636.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 257049 + 379456 = 507^2 + 616^2 .

It is not a de Polignac number, because 636505 - 2⁵ = 636473 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 636505.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 63646 + ... + 63655.

It is an arithmetic number, because the mean of its divisors is an integer number (190953).

2⁶³⁶⁵⁰⁵ is an apocalyptic number.

It is an amenable number.

636505 is a deficient number, since it is larger than the sum of its proper divisors (127307).

636505 is a wasteful number, since it uses less digits than its factorization.

636505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127306.

The product of its (nonzero) digits is 2700, while the sum is 25.

The square root of 636505 is about 797.8126346455. The cubic root of 636505 is about 86.0202314039.

The spelling of 636505 in words is "six hundred thirty-six thousand, five hundred five".