20566161 has 48 divisors (see below), whose sum is σ = 37739520. Its totient is φ = 10481760.

The previous prime is 20566159. The next prime is 20566171. The reversal of 20566161 is 16166502.

It is a happy number.

It is not a de Polignac number, because 20566161 - 2¹ = 20566159 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20566121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 40636 + ... + 41138.

It is an arithmetic number, because the mean of its divisors is an integer number (786240).

Almost surely, 2^20566161 is an apocalyptic number.

20566161 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20566161 is a deficient number, since it is larger than the sum of its proper divisors (17173359).

20566161 is a wasteful number, since it uses less digits than its factorization.

20566161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 586 (or 583 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 20566161 is about 4534.9929437652. The cubic root of 20566161 is about 273.9792949705.

It can be divided in two parts, 205 and 66161, that added together give a palindrome (66366).

The spelling of 20566161 in words is "twenty million, five hundred sixty-six thousand, one hundred sixty-one".