20581161 has 16 divisors (see below), whose sum is σ = 29217600. Its totient is φ = 12849408.

The previous prime is 20581153. The next prime is 20581163. The reversal of 20581161 is 16118502.

It is not a de Polignac number, because 20581161 - 2³ = 20581153 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20581163) 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 15 ways as a sum of consecutive naturals, for example, 3045 + ... + 7101.

It is an arithmetic number, because the mean of its divisors is an integer number (1826100).

Almost surely, 2^20581161 is an apocalyptic number.

It is an amenable number.

20581161 is a deficient number, since it is larger than the sum of its proper divisors (8636439).

20581161 is a wasteful number, since it uses less digits than its factorization.

20581161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4168.

The product of its (nonzero) digits is 480, while the sum is 24.

The square root of 20581161 is about 4536.6464486446. The cubic root of 20581161 is about 274.0458880291.

Adding to 20581161 its reverse (16118502), we get a palindrome (36699663).

The spelling of 20581161 in words is "twenty million, five hundred eighty-one thousand, one hundred sixty-one".