20216165 has 4 divisors (see below), whose sum is σ = 24259404. Its totient is φ = 16172928.

The previous prime is 20216137. The next prime is 20216167. The reversal of 20216165 is 56161202.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56161202 = 2 ⋅28080601.

It can be written as a sum of positive squares in 2 ways, for example, as 12609601 + 7606564 = 3551^2 + 2758^2 .

It is a cyclic number.

It is not a de Polignac number, because 20216165 - 2²² = 16021861 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 20216165.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20216167) 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 3 ways as a sum of consecutive naturals, for example, 2021612 + ... + 2021621.

It is an arithmetic number, because the mean of its divisors is an integer number (6064851).

Almost surely, 2^20216165 is an apocalyptic number.

It is an amenable number.

20216165 is a deficient number, since it is larger than the sum of its proper divisors (4043239).

20216165 is an equidigital number, since it uses as much as digits as its factorization.

20216165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4043238.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 20216165 is about 4496.2389838620. The cubic root of 20216165 is about 272.4161962090.

Adding to 20216165 its reverse (56161202), we get a palindrome (76377367).

The spelling of 20216165 in words is "twenty million, two hundred sixteen thousand, one hundred sixty-five".