636040 has 16 divisors (see below), whose sum is σ = 1431180. Its totient is φ = 254400.

The previous prime is 636023. The next prime is 636043. The reversal of 636040 is 40636.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 586756 + 49284 = 766^2 + 222^2 .

It is a junction number, because it is equal to n+sod(n) for n = 635999 and 636017.

It is not an unprimeable number, because it can be changed into a prime (636043) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7911 + ... + 7990.

2⁶³⁶⁰⁴⁰ is an apocalyptic number.

It is an amenable number.

636040 is an abundant number, since it is smaller than the sum of its proper divisors (795140).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

636040 is a wasteful number, since it uses less digits than its factorization.

636040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15912 (or 15908 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 19.

The square root of 636040 is about 797.5211595939. The cubic root of 636040 is about 85.9992788834. Note that the first 3 decimals are identical.

Adding to 636040 its reverse (40636), we get a palindrome (676676).

It can be divided in two parts, 6360 and 40, that added together give a square (6400 = 80²).

The spelling of 636040 in words is "six hundred thirty-six thousand, forty".