20705717 has 4 divisors (see below), whose sum is σ = 20919276. Its totient is φ = 20492160.

The previous prime is 20705701. The next prime is 20705753. The reversal of 20705717 is 71750702.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10201636 + 10504081 = 3194^2 + 3241^2 .

It is a cyclic number.

It is not a de Polignac number, because 20705717 - 2⁴ = 20705701 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20705717.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20705767) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 106634 + ... + 106827.

It is an arithmetic number, because the mean of its divisors is an integer number (5229819).

Almost surely, 2^20705717 is an apocalyptic number.

It is an amenable number.

20705717 is a deficient number, since it is larger than the sum of its proper divisors (213559).

20705717 is an equidigital number, since it uses as much as digits as its factorization.

20705717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213558.

The product of its (nonzero) digits is 3430, while the sum is 29.

The square root of 20705717 is about 4550.3535027512. The cubic root of 20705717 is about 274.5976131576.

The spelling of 20705717 in words is "twenty million, seven hundred five thousand, seven hundred seventeen".