636643 has 8 divisors (see below), whose sum is σ = 735488. Its totient is φ = 539784.

The previous prime is 636631. The next prime is 636653. The reversal of 636643 is 346636.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-636643 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (636613) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 280 + ... + 1162.

It is an arithmetic number, because the mean of its divisors is an integer number (91936).

2⁶³⁶⁶⁴³ is an apocalyptic number.

636643 is a deficient number, since it is larger than the sum of its proper divisors (98845).

636643 is a wasteful number, since it uses less digits than its factorization.

636643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 993.

The product of its digits is 7776, while the sum is 28.

The square root of 636643 is about 797.8991164301. The cubic root of 636643 is about 86.0264476076.

The spelling of 636643 in words is "six hundred thirty-six thousand, six hundred forty-three".