636644 has 6 divisors (see below), whose sum is σ = 1114134. Its totient is φ = 318320.

The previous prime is 636631. The next prime is 636653. The reversal of 636644 is 446636.

It can be written as a sum of positive squares in only one way, i.e., 624100 + 12544 = 790^2 + 112^2 .

It is a plaindrome in base 8.

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 as a sum of consecutive naturals, namely, 79577 + ... + 79584.

It is an arithmetic number, because the mean of its divisors is an integer number (185689).

2⁶³⁶⁶⁴⁴ is an apocalyptic number.

It is an amenable number.

636644 is a deficient number, since it is larger than the sum of its proper divisors (477490).

636644 is a wasteful number, since it uses less digits than its factorization.

636644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159165 (or 159163 counting only the distinct ones).

The product of its digits is 10368, while the sum is 29.

The square root of 636644 is about 797.8997430755. The cubic root of 636644 is about 86.0264926492.

The spelling of 636644 in words is "six hundred thirty-six thousand, six hundred forty-four".