20805065 has 4 divisors (see below), whose sum is σ = 24966084. Its totient is φ = 16644048.

The previous prime is 20805049. The next prime is 20805089. The reversal of 20805065 is 56050802.

20805065 is nontrivially palindromic in base 8.

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 15912121 + 4892944 = 3989^2 + 2212^2 .

It is a cyclic number.

It is not a de Polignac number, because 20805065 - 2⁴ = 20805049 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a zygodrome in base 3.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2080502 + ... + 2080511.

It is an arithmetic number, because the mean of its divisors is an integer number (6241521).

Almost surely, 2^20805065 is an apocalyptic number.

It is an amenable number.

20805065 is a deficient number, since it is larger than the sum of its proper divisors (4161019).

20805065 is an equidigital number, since it uses as much as digits as its factorization.

20805065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4161018.

The product of its (nonzero) digits is 2400, while the sum is 26.

The square root of 20805065 is about 4561.2569539547. The cubic root of 20805065 is about 275.0360944359.

Adding to 20805065 its reverse (56050802), we get a palindrome (76855867).

The spelling of 20805065 in words is "twenty million, eight hundred five thousand, sixty-five".