20730 has 16 divisors (see below), whose sum is σ = 49824. Its totient is φ = 5520.

The previous prime is 20719. The next prime is 20731. The reversal of 20730 is 3702.

20730 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a plaindrome in base 14.

It is a nialpdrome in base 12 and base 15.

It is a zygodrome in base 4 and base 14.

It is not an unprimeable number, because it can be changed into a prime (20731) by changing a digit.

20730 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 316 + ... + 375.

It is an arithmetic number, because the mean of its divisors is an integer number (3114).

2²⁰⁷³⁰ is an apocalyptic number.

20730 is an abundant number, since it is smaller than the sum of its proper divisors (29094).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24912).

20730 is a wasteful number, since it uses less digits than its factorization.

20730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 701.

The product of its (nonzero) digits is 42, while the sum is 12.

The square root of 20730 is about 143.9791651594. The cubic root of 20730 is about 27.4704917642.

The spelling of 20730 in words is "twenty thousand, seven hundred thirty".