20656 has 10 divisors (see below), whose sum is σ = 40052. Its totient is φ = 10320.

The previous prime is 20641. The next prime is 20663. The reversal of 20656 is 65602.

It is a plaindrome in base 11.

It is a nialpdrome in base 12.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 630 + ... + 661.

2²⁰⁶⁵⁶ is an apocalyptic number.

It is an amenable number.

20656 is a deficient number, since it is larger than the sum of its proper divisors (19396).

20656 is a wasteful number, since it uses less digits than its factorization.

20656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1299 (or 1293 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 20656 is about 143.7219537858. The cubic root of 20656 is about 27.4377656016.

It can be divided in two parts, 206 and 56, that added together give a palindrome (262).

The spelling of 20656 in words is "twenty thousand, six hundred fifty-six".