20565155 has 32 divisors (see below), whose sum is σ = 28957824. Its totient is φ = 13879296.

The previous prime is 20565133. The next prime is 20565157. The reversal of 20565155 is 55156502.

It is a cyclic number.

It is not a de Polignac number, because 20565155 - 2⁶ = 20565091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20565157) 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 31 ways as a sum of consecutive naturals, for example, 40634 + ... + 41136.

It is an arithmetic number, because the mean of its divisors is an integer number (904932).

Almost surely, 2^20565155 is an apocalyptic number.

20565155 is a deficient number, since it is larger than the sum of its proper divisors (8392669).

20565155 is a wasteful number, since it uses less digits than its factorization.

20565155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 575.

The product of its (nonzero) digits is 7500, while the sum is 29.

The square root of 20565155 is about 4534.8820271315. The cubic root of 20565155 is about 273.9748276376.

The spelling of 20565155 in words is "twenty million, five hundred sixty-five thousand, one hundred fifty-five".