645606555767 has 2 divisors, whose sum is σ = 645606555768. Its totient is φ = 645606555766.

The previous prime is 645606555761. The next prime is 645606555793. The reversal of 645606555767 is 767555606546.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 645606555767 - 2⁶ = 645606555703 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645606555761) 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, 322803277883 + 322803277884.

It is an arithmetic number, because the mean of its divisors is an integer number (322803277884).

Almost surely, 2^645606555767 is an apocalyptic number.

645606555767 is a deficient number, since it is larger than the sum of its proper divisors (1).

645606555767 is an equidigital number, since it uses as much as digits as its factorization.

645606555767 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 158760000, while the sum is 62.

The spelling of 645606555767 in words is "six hundred forty-five billion, six hundred six million, five hundred fifty-five thousand, seven hundred sixty-seven".