20565181 has 16 divisors (see below), whose sum is σ = 25696384. Its totient is φ = 16023744.

The previous prime is 20565173. The next prime is 20565191. The reversal of 20565181 is 18156502.

It is a cyclic number.

It is not a de Polignac number, because 20565181 - 2³ = 20565173 is a prime.

It is a super-2 number, since 2×20565181² = 845853339125522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20565101) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4411 + ... + 7783.

It is an arithmetic number, because the mean of its divisors is an integer number (1606024).

Almost surely, 2^20565181 is an apocalyptic number.

It is an amenable number.

20565181 is a deficient number, since it is larger than the sum of its proper divisors (5131203).

20565181 is a wasteful number, since it uses less digits than its factorization.

20565181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3460.

The product of its (nonzero) digits is 2400, while the sum is 28.

The square root of 20565181 is about 4534.8848937983. The cubic root of 20565181 is about 273.9749430973.

The spelling of 20565181 in words is "twenty million, five hundred sixty-five thousand, one hundred eighty-one".