20845165 has 16 divisors (see below), whose sum is σ = 27806976. Its totient is φ = 14872000.

The previous prime is 20845163. The next prime is 20845189. The reversal of 20845165 is 56154802.

It is not a de Polignac number, because 20845165 - 2¹ = 20845163 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20845163) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 661 + ... + 6490.

It is an arithmetic number, because the mean of its divisors is an integer number (1737936).

Almost surely, 2^20845165 is an apocalyptic number.

It is an amenable number.

20845165 is a deficient number, since it is larger than the sum of its proper divisors (6961811).

20845165 is a wasteful number, since it uses less digits than its factorization.

20845165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7220.

The product of its (nonzero) digits is 9600, while the sum is 31.

The square root of 20845165 is about 4565.6505560544. The cubic root of 20845165 is about 275.2126839535.

Adding to 20845165 its reverse (56154802), we get a palindrome (76999967).

The spelling of 20845165 in words is "twenty million, eight hundred forty-five thousand, one hundred sixty-five".