20684897 has 2 divisors, whose sum is σ = 20684898. Its totient is φ = 20684896.

The previous prime is 20684879. The next prime is 20684899. The reversal of 20684897 is 79848602.

Together with previous prime (20684879) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20511841 + 173056 = 4529^2 + 416^2 .

It is a cyclic number.

It is not a de Polignac number, because 20684897 - 2⁸ = 20684641 is a prime.

Together with 20684899, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20684899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10342448 + 10342449.

It is an arithmetic number, because the mean of its divisors is an integer number (10342449).

Almost surely, 2^20684897 is an apocalyptic number.

It is an amenable number.

20684897 is a deficient number, since it is larger than the sum of its proper divisors (1).

20684897 is an equidigital number, since it uses as much as digits as its factorization.

20684897 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 193536, while the sum is 44.

The square root of 20684897 is about 4548.0651930244. The cubic root of 20684897 is about 274.5055445500.

The spelling of 20684897 in words is "twenty million, six hundred eighty-four thousand, eight hundred ninety-seven".