20718305 has 16 divisors (see below), whose sum is σ = 25622784. Its totient is φ = 16074240.

The previous prime is 20718287. The next prime is 20718311. The reversal of 20718305 is 50381702.

It is not a de Polignac number, because 20718305 - 2⁶ = 20718241 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 30449 + ... + 31121.

It is an arithmetic number, because the mean of its divisors is an integer number (1601424).

Almost surely, 2^20718305 is an apocalyptic number.

It is an amenable number.

20718305 is a deficient number, since it is larger than the sum of its proper divisors (4904479).

20718305 is a wasteful number, since it uses less digits than its factorization.

20718305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 856.

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 20718305 is about 4551.7364818276. The cubic root of 20718305 is about 274.6532489112.

The spelling of 20718305 in words is "twenty million, seven hundred eighteen thousand, three hundred five".