646636 has 6 divisors (see below), whose sum is σ = 1131620. Its totient is φ = 323316.

The previous prime is 646631. The next prime is 646637. The reversal of 646636 is 636646.

It is a junction number, because it is equal to n+sod(n) for n = 646598 and 646607.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 646636.

It is not an unprimeable number, because it can be changed into a prime (646631) by changing a digit.

646636 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 as a sum of consecutive naturals, namely, 80826 + ... + 80833.

2⁶⁴⁶⁶³⁶ is an apocalyptic number.

It is an amenable number.

646636 is a deficient number, since it is larger than the sum of its proper divisors (484984).

646636 is a wasteful number, since it uses less digits than its factorization.

646636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161663 (or 161661 counting only the distinct ones).

The product of its digits is 15552, while the sum is 31.

The square root of 646636 is about 804.1368042815. The cubic root of 646636 is about 86.4742146404.

The spelling of 646636 in words is "six hundred forty-six thousand, six hundred thirty-six".