656641289 has 2 divisors, whose sum is σ = 656641290. Its totient is φ = 656641288.

The previous prime is 656641253. The next prime is 656641291. The reversal of 656641289 is 982146656.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 335622400 + 321018889 = 18320^2 + 17917^2 .

It is a cyclic number.

It is not a de Polignac number, because 656641289 - 2⁸ = 656641033 is a prime.

Together with 656641291, 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 (656641189) 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, 328320644 + 328320645.

It is an arithmetic number, because the mean of its divisors is an integer number (328320645).

Almost surely, 2^656641289 is an apocalyptic number.

It is an amenable number.

656641289 is a deficient number, since it is larger than the sum of its proper divisors (1).

656641289 is an equidigital number, since it uses as much as digits as its factorization.

656641289 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 622080, while the sum is 47.

The square root of 656641289 is about 25625.0129560943. The cubic root of 656641289 is about 869.1793419522.

The spelling of 656641289 in words is "six hundred fifty-six million, six hundred forty-one thousand, two hundred eighty-nine".