20717161 has 4 divisors (see below), whose sum is σ = 21009024. Its totient is φ = 20425300.

The previous prime is 20717159. The next prime is 20717167. The reversal of 20717161 is 16171702.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16171702 = 2 ⋅8085851.

It is a cyclic number.

It is not a de Polignac number, because 20717161 - 2¹ = 20717159 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20717167) 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 3 ways as a sum of consecutive naturals, for example, 145825 + ... + 145966.

It is an arithmetic number, because the mean of its divisors is an integer number (5252256).

Almost surely, 2^20717161 is an apocalyptic number.

It is an amenable number.

20717161 is a deficient number, since it is larger than the sum of its proper divisors (291863).

20717161 is an equidigital number, since it uses as much as digits as its factorization.

20717161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 291862.

The product of its (nonzero) digits is 588, while the sum is 25.

The square root of 20717161 is about 4551.6108137669. The cubic root of 20717161 is about 274.6481936537.

Adding to 20717161 its reverse (16171702), we get a palindrome (36888863).

The spelling of 20717161 in words is "twenty million, seven hundred seventeen thousand, one hundred sixty-one".