20718717 has 4 divisors (see below), whose sum is σ = 27624960. Its totient is φ = 13812476.

The previous prime is 20718703. The next prime is 20718739. The reversal of 20718717 is 71781702.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20718717 - 2⁴ = 20718701 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20718017) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3453117 + ... + 3453122.

It is an arithmetic number, because the mean of its divisors is an integer number (6906240).

Almost surely, 2^20718717 is an apocalyptic number.

It is an amenable number.

20718717 is a deficient number, since it is larger than the sum of its proper divisors (6906243).

20718717 is an equidigital number, since it uses as much as digits as its factorization.

20718717 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6906242.

The product of its (nonzero) digits is 5488, while the sum is 33.

The square root of 20718717 is about 4551.7817390556. The cubic root of 20718717 is about 274.6550694654.

The spelling of 20718717 in words is "twenty million, seven hundred eighteen thousand, seven hundred seventeen".