20420287 has 2 divisors, whose sum is σ = 20420288. Its totient is φ = 20420286.

The previous prime is 20420243. The next prime is 20420293. The reversal of 20420287 is 78202402.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20420287 - 2¹¹ = 20418239 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20420207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10210143 + 10210144.

It is an arithmetic number, because the mean of its divisors is an integer number (10210144).

Almost surely, 2^20420287 is an apocalyptic number.

20420287 is a deficient number, since it is larger than the sum of its proper divisors (1).

20420287 is an equidigital number, since it uses as much as digits as its factorization.

20420287 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1792, while the sum is 25.

The square root of 20420287 is about 4518.8811668376. The cubic root of 20420287 is about 273.3299869046.

Adding to 20420287 its reverse (78202402), we get a palindrome (98622689).

The spelling of 20420287 in words is "twenty million, four hundred twenty thousand, two hundred eighty-seven".