20665705 has 8 divisors (see below), whose sum is σ = 24881472. Its totient is φ = 16477488.

The previous prime is 20665669. The next prime is 20665739. The reversal of 20665705 is 50756602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20665705 - 2⁷ = 20665577 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5197 + ... + 8266.

It is an arithmetic number, because the mean of its divisors is an integer number (3110184).

Almost surely, 2^20665705 is an apocalyptic number.

It is an amenable number.

20665705 is a deficient number, since it is larger than the sum of its proper divisors (4215767).

20665705 is a wasteful number, since it uses less digits than its factorization.

20665705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13775.

The product of its (nonzero) digits is 12600, while the sum is 31.

The square root of 20665705 is about 4545.9547951998. The cubic root of 20665705 is about 274.4206204205.

The spelling of 20665705 in words is "twenty million, six hundred sixty-five thousand, seven hundred five".