20711665 has 8 divisors (see below), whose sum is σ = 26765928. Its totient is φ = 15294720.

The previous prime is 20711659. The next prime is 20711671. The reversal of 20711665 is 56611702.

It is an interprime number because it is at equal distance from previous prime (20711659) and next prime (20711671).

It can be written as a sum of positive squares in 4 ways, for example, as 3038049 + 17673616 = 1743^2 + 4204^2 .

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

It is not a de Polignac number, because 20711665 - 2²¹ = 18614513 is a prime.

It is a Duffinian 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 7 ways as a sum of consecutive naturals, for example, 159256 + ... + 159385.

It is an arithmetic number, because the mean of its divisors is an integer number (3345741).

Almost surely, 2^20711665 is an apocalyptic number.

It is an amenable number.

20711665 is a deficient number, since it is larger than the sum of its proper divisors (6054263).

20711665 is a wasteful number, since it uses less digits than its factorization.

20711665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 318659.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 20711665 is about 4551.0070314162. The cubic root of 20711665 is about 274.6239046118.

The spelling of 20711665 in words is "twenty million, seven hundred eleven thousand, six hundred sixty-five".