20172165 has 64 divisors (see below), whose sum is σ = 37158912. Its totient is φ = 9273600.

The previous prime is 20172161. The next prime is 20172193. The reversal of 20172165 is 56127102.

It is not a de Polignac number, because 20172165 - 2² = 20172161 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20172161) 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 63 ways as a sum of consecutive naturals, for example, 284080 + ... + 284150.

It is an arithmetic number, because the mean of its divisors is an integer number (580608).

Almost surely, 2^20172165 is an apocalyptic number.

It is an amenable number.

20172165 is a deficient number, since it is larger than the sum of its proper divisors (16986747).

20172165 is a wasteful number, since it uses less digits than its factorization.

20172165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170.

The product of its (nonzero) digits is 840, while the sum is 24.

The square root of 20172165 is about 4491.3433402491. The cubic root of 20172165 is about 272.2184168719.

Adding to 20172165 its reverse (56127102), we get a palindrome (76299267).

The spelling of 20172165 in words is "twenty million, one hundred seventy-two thousand, one hundred sixty-five".