646640117 has 2 divisors, whose sum is σ = 646640118. Its totient is φ = 646640116.

The previous prime is 646640087. The next prime is 646640123. The reversal of 646640117 is 711046646.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 603488356 + 43151761 = 24566^2 + 6569^2 .

It is a cyclic number.

It is not a de Polignac number, because 646640117 - 2¹⁶ = 646574581 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 (646640317) 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, 323320058 + 323320059.

It is an arithmetic number, because the mean of its divisors is an integer number (323320059).

Almost surely, 2^646640117 is an apocalyptic number.

It is an amenable number.

646640117 is a deficient number, since it is larger than the sum of its proper divisors (1).

646640117 is an equidigital number, since it uses as much as digits as its factorization.

646640117 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24192, while the sum is 35.

The square root of 646640117 is about 25429.1194696159. The cubic root of 646640117 is about 864.7439816127.

The spelling of 646640117 in words is "six hundred forty-six million, six hundred forty thousand, one hundred seventeen".