20431161 has 24 divisors (see below), whose sum is σ = 32019624. Its totient is φ = 12503040.

The previous prime is 20431123. The next prime is 20431171. The reversal of 20431161 is 16113402.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 3980025 + 16451136 = 1995^2 + 4056^2 .

It is not a de Polignac number, because 20431161 - 2⁶ = 20431097 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20431121) 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 23 ways as a sum of consecutive naturals, for example, 4645 + ... + 7901.

It is an arithmetic number, because the mean of its divisors is an integer number (1334151).

Almost surely, 2^20431161 is an apocalyptic number.

It is an amenable number.

20431161 is a deficient number, since it is larger than the sum of its proper divisors (11588463).

20431161 is a wasteful number, since it uses less digits than its factorization.

20431161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3321 (or 3318 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 20431161 is about 4520.0841806320. The cubic root of 20431161 is about 273.3784952477.

Adding to 20431161 its reverse (16113402), we get a palindrome (36544563).

The spelling of 20431161 in words is "twenty million, four hundred thirty-one thousand, one hundred sixty-one".