20628 has 24 divisors (see below), whose sum is σ = 53760. Its totient is φ = 6840.

The previous prime is 20627. The next prime is 20639. The reversal of 20628 is 82602.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nialpdrome in base 12.

It is a self number, because there is not a number n which added to its sum of digits gives 20628.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20627) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 13 + ... + 203.

It is an arithmetic number, because the mean of its divisors is an integer number (2240).

2²⁰⁶²⁸ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20628, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26880).

20628 is an abundant number, since it is smaller than the sum of its proper divisors (33132).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20628 is a wasteful number, since it uses less digits than its factorization.

20628 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204 (or 196 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 20628 is about 143.6245104430. The cubic root of 20628 is about 27.4253623478.

The spelling of 20628 in words is "twenty thousand, six hundred twenty-eight".