656042909 has 2 divisors, whose sum is σ = 656042910. Its totient is φ = 656042908.

The previous prime is 656042813. The next prime is 656042921. The reversal of 656042909 is 909240656.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 427579684 + 228463225 = 20678^2 + 15115^2 .

It is a cyclic number.

It is not a de Polignac number, because 656042909 - 2¹⁶ = 655977373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (656042929) 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, 328021454 + 328021455.

It is an arithmetic number, because the mean of its divisors is an integer number (328021455).

Almost surely, 2^656042909 is an apocalyptic number.

It is an amenable number.

656042909 is a deficient number, since it is larger than the sum of its proper divisors (1).

656042909 is an equidigital number, since it uses as much as digits as its factorization.

656042909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 116640, while the sum is 41.

The square root of 656042909 is about 25613.3345935276. The cubic root of 656042909 is about 868.9152415939.

The spelling of 656042909 in words is "six hundred fifty-six million, forty-two thousand, nine hundred nine".