20648 has 16 divisors (see below), whose sum is σ = 40500. Its totient is φ = 9856.

The previous prime is 20641. The next prime is 20663. The reversal of 20648 is 84602.

It can be written as a sum of positive squares in 2 ways, for example, as 20164 + 484 = 142^2 + 22^2 .

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 20648.

It is not an unprimeable number, because it can be changed into a prime (20641) by changing a digit.

20648 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 (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 188 + ... + 276.

2²⁰⁶⁴⁸ is an apocalyptic number.

It is an amenable number.

20648 is a deficient number, since it is larger than the sum of its proper divisors (19852).

20648 is a wasteful number, since it uses less digits than its factorization.

20648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124 (or 120 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 20648 is about 143.6941195735. The cubic root of 20648 is about 27.4342229591.

The spelling of 20648 in words is "twenty thousand, six hundred forty-eight".