20418 has 16 divisors (see below), whose sum is σ = 42336. Its totient is φ = 6560.

The previous prime is 20411. The next prime is 20431. The reversal of 20418 is 81402.

It is a plaindrome in base 7.

It is a nialpdrome in base 12.

It is a junction number, because it is equal to n+sod(n) for n = 20397 and 20406.

It is not an unprimeable number, because it can be changed into a prime (20411) by changing a digit.

20418 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, 205 + ... + 287.

It is an arithmetic number, because the mean of its divisors is an integer number (2646).

2²⁰⁴¹⁸ is an apocalyptic number.

20418 is an abundant number, since it is smaller than the sum of its proper divisors (21918).

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 (21168).

20418 is a wasteful number, since it uses less digits than its factorization.

20418 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129.

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 20418 is about 142.8915672809. The cubic root of 20418 is about 27.3319782526.

It can be divided in two parts, 204 and 18, that added together give a palindrome (222).

The spelling of 20418 in words is "twenty thousand, four hundred eighteen".