20718243 has 48 divisors (see below), whose sum is σ = 37791936. Its totient is φ = 10644480.

The previous prime is 20718241. The next prime is 20718259. The reversal of 20718243 is 34281702.

It is not a de Polignac number, because 20718243 - 2¹ = 20718241 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20718241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 33271 + ... + 33887.

It is an arithmetic number, because the mean of its divisors is an integer number (787332).

Almost surely, 2^20718243 is an apocalyptic number.

20718243 is a deficient number, since it is larger than the sum of its proper divisors (17073693).

20718243 is a wasteful number, since it uses less digits than its factorization.

20718243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 684 (or 681 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 20718243 is about 4551.7296712349. The cubic root of 20718243 is about 274.6529749422.

Adding to 20718243 its reverse (34281702), we get a palindrome (54999945).

The spelling of 20718243 in words is "twenty million, seven hundred eighteen thousand, two hundred forty-three".