20724287 has 2 divisors, whose sum is σ = 20724288. Its totient is φ = 20724286.

The previous prime is 20724259. The next prime is 20724349. The reversal of 20724287 is 78242702.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20724287 - 2¹⁴ = 20707903 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20724217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10362143 + 10362144.

It is an arithmetic number, because the mean of its divisors is an integer number (10362144).

Almost surely, 2^20724287 is an apocalyptic number.

20724287 is a deficient number, since it is larger than the sum of its proper divisors (1).

20724287 is an equidigital number, since it uses as much as digits as its factorization.

20724287 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12544, while the sum is 32.

The square root of 20724287 is about 4552.3935462567. The cubic root of 20724287 is about 274.6796799285.

Adding to 20724287 its reverse (78242702), we get a palindrome (98966989).

The spelling of 20724287 in words is "twenty million, seven hundred twenty-four thousand, two hundred eighty-seven".