20718 has 12 divisors (see below), whose sum is σ = 44928. Its totient is φ = 6900.

The previous prime is 20717. The next prime is 20719. The reversal of 20718 is 81702.

20718 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (20717) and next prime (20719).

It is a Harshad number since it is a multiple of its sum of digits (18), and also a Moran number because the ratio is a prime number: 1151 = 20718 / (2 + 0 + 7 + 1 + 8).

It is a plaindrome in base 14.

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 20718.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20717) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 558 + ... + 593.

It is an arithmetic number, because the mean of its divisors is an integer number (3744).

2²⁰⁷¹⁸ is an apocalyptic number.

20718 is an abundant number, since it is smaller than the sum of its proper divisors (24210).

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

20718 is a wasteful number, since it uses less digits than its factorization.

20718 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1159 (or 1156 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 18.

The square root of 20718 is about 143.9374864307. The cubic root of 20718 is about 27.4651901155.

Adding to 20718 its sum of digits (18), we get a 4-th power (20736 = 12⁴).

It can be divided in two parts, 207 and 18, that added together give a square (225 = 15²).

The spelling of 20718 in words is "twenty thousand, seven hundred eighteen".