636320 has 48 divisors (see below), whose sum is σ = 1555848. Its totient is φ = 245760.

The previous prime is 636319. The next prime is 636331. The reversal of 636320 is 23636.

636320 = 28² + 29² + ... + 124².

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 327184 + 309136 = 572^2 + 556^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 636292 and 636301.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6512 + ... + 6608.

2⁶³⁶³²⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 636320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (777924).

636320 is an abundant number, since it is smaller than the sum of its proper divisors (919528).

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

636320 is a wasteful number, since it uses less digits than its factorization.

636320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 153 (or 145 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 20.

The square root of 636320 is about 797.6966842102. The cubic root of 636320 is about 86.0118966776.

Adding to 636320 its reverse (23636), we get a palindrome (659956).

It can be divided in two parts, 6363 and 20, that multiplied together give a triangular number (127260 = T₅₀₄).

The spelling of 636320 in words is "six hundred thirty-six thousand, three hundred twenty".