20405165 has 16 divisors (see below), whose sum is σ = 26813376. Its totient is φ = 14784000.

The previous prime is 20405153. The next prime is 20405173. The reversal of 20405165 is 56150402.

It is not a de Polignac number, because 20405165 - 2⁶ = 20405101 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 20405165.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18890 + ... + 19940.

It is an arithmetic number, because the mean of its divisors is an integer number (1675836).

Almost surely, 2^20405165 is an apocalyptic number.

It is an amenable number.

20405165 is a deficient number, since it is larger than the sum of its proper divisors (6408211).

20405165 is a wasteful number, since it uses less digits than its factorization.

20405165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1420.

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 20405165 is about 4517.2076551781. The cubic root of 20405165 is about 273.2624998223.

Adding to 20405165 its reverse (56150402), we get a palindrome (76555567).

The spelling of 20405165 in words is "twenty million, four hundred five thousand, one hundred sixty-five".