20718031 has 2 divisors, whose sum is σ = 20718032. Its totient is φ = 20718030.

The previous prime is 20718017. The next prime is 20718073. The reversal of 20718031 is 13081702.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20718031 - 2⁷ = 20717903 is a prime.

It is a super-2 number, since 2×20718031² = 858473617033922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20717993 and 20718011.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20718011) 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 as a sum of consecutive naturals, namely, 10359015 + 10359016.

It is an arithmetic number, because the mean of its divisors is an integer number (10359016).

Almost surely, 2^20718031 is an apocalyptic number.

20718031 is a deficient number, since it is larger than the sum of its proper divisors (1).

20718031 is an equidigital number, since it uses as much as digits as its factorization.

20718031 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 20718031 is about 4551.7063833248. The cubic root of 20718031 is about 274.6520381410.

Adding to 20718031 its reverse (13081702), we get a palindrome (33799733).

The spelling of 20718031 in words is "twenty million, seven hundred eighteen thousand, thirty-one".