20313281 has 2 divisors, whose sum is σ = 20313282. Its totient is φ = 20313280.

The previous prime is 20313247. The next prime is 20313343. The reversal of 20313281 is 18231302.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20106256 + 207025 = 4484^2 + 455^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20313281 is a prime.

It is a super-2 number, since 2×20313281² = 825258769969922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (20313581) 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, 10156640 + 10156641.

It is an arithmetic number, because the mean of its divisors is an integer number (10156641).

Almost surely, 2^20313281 is an apocalyptic number.

It is an amenable number.

20313281 is a deficient number, since it is larger than the sum of its proper divisors (1).

20313281 is an equidigital number, since it uses as much as digits as its factorization.

20313281 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 20313281 is about 4507.0257376678. The cubic root of 20313281 is about 272.8517176552.

Adding to 20313281 its reverse (18231302), we get a palindrome (38544583).

The spelling of 20313281 in words is "twenty million, three hundred thirteen thousand, two hundred eighty-one".