20718018 has 80 divisors (see below), whose sum is σ = 50181120. Its totient is φ = 6368544.

The previous prime is 20718017. The next prime is 20718031. The reversal of 20718018 is 81081702.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 20717982 and 20718000.

It is not an unprimeable number, because it can be changed into a prime (20718011) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 163071 + ... + 163197.

It is an arithmetic number, because the mean of its divisors is an integer number (627264).

Almost surely, 2^20718018 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20718018, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25090560).

20718018 is an abundant number, since it is smaller than the sum of its proper divisors (29463102).

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

20718018 is a wasteful number, since it uses less digits than its factorization.

20718018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213 (or 204 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 27.

The square root of 20718018 is about 4551.7049552887. The cubic root of 20718018 is about 274.6519806954.

It can be divided in two parts, 207 and 18018, that added together give a square (18225 = 135²).

The spelling of 20718018 in words is "twenty million, seven hundred eighteen thousand, eighteen".