20717231 has 2 divisors, whose sum is σ = 20717232. Its totient is φ = 20717230.

The previous prime is 20717219. The next prime is 20717251. The reversal of 20717231 is 13271702.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20717231 - 2⁶ = 20717167 is a prime.

It is a super-2 number, since 2×20717231² = 858407320614722, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20717197 and 20717206.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20717251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10358615 + 10358616.

It is an arithmetic number, because the mean of its divisors is an integer number (10358616).

Almost surely, 2^20717231 is an apocalyptic number.

20717231 is a deficient number, since it is larger than the sum of its proper divisors (1).

20717231 is an equidigital number, since it uses as much as digits as its factorization.

20717231 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 588, while the sum is 23.

The square root of 20717231 is about 4551.6185033458. The cubic root of 20717231 is about 274.6485029843.

Adding to 20717231 its reverse (13271702), we get a palindrome (33988933).

The spelling of 20717231 in words is "twenty million, seven hundred seventeen thousand, two hundred thirty-one".