636637 has 6 divisors (see below), whose sum is σ = 660218. Its totient is φ = 613872.

The previous prime is 636631. The next prime is 636653. The reversal of 636637 is 736636.

It can be written as a sum of positive squares in 3 ways, for example, as 133956 + 502681 = 366^2 + 709^2 .

It is not a de Polignac number, because 636637 - 2¹⁹ = 112349 is a prime.

It is a Duffinian number.

It is a plaindrome in base 8.

It is a junction number, because it is equal to n+sod(n) for n = 636599 and 636608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (636631) 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, 463 + ... + 1219.

2⁶³⁶⁶³⁷ is an apocalyptic number.

It is an amenable number.

636637 is a deficient number, since it is larger than the sum of its proper divisors (23581).

636637 is an equidigital number, since it uses as much as digits as its factorization.

636637 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 815 (or 786 counting only the distinct ones).

The product of its digits is 13608, while the sum is 31.

The square root of 636637 is about 797.8953565475. The cubic root of 636637 is about 86.0261773565.

Subtracting 636637 from its reverse (736636), we obtain a palindrome (99999).

The spelling of 636637 in words is "six hundred thirty-six thousand, six hundred thirty-seven".