644510440041157 has 2 divisors, whose sum is σ = 644510440041158. Its totient is φ = 644510440041156.

The previous prime is 644510440041121. The next prime is 644510440041173. The reversal of 644510440041157 is 751140044015446.

644510440041157 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 626959082800801 + 17551357240356 = 25039151^2 + 4189434^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644510440041157 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644510440041557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322255220020578 + 322255220020579.

It is an arithmetic number, because the mean of its divisors is an integer number (322255220020579).

Almost surely, 2^{644510440041157} is an apocalyptic number.

It is an amenable number.

644510440041157 is a deficient number, since it is larger than the sum of its proper divisors (1).

644510440041157 is an equidigital number, since it uses as much as digits as its factorization.

644510440041157 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1075200, while the sum is 46.

The spelling of 644510440041157 in words is "six hundred forty-four trillion, five hundred ten billion, four hundred forty million, forty-one thousand, one hundred fifty-seven".