645256567 has 2 divisors, whose sum is σ = 645256568. Its totient is φ = 645256566.

The previous prime is 645256541. The next prime is 645256603. The reversal of 645256567 is 765652546.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 645256567 - 2⁷ = 645256439 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645256517) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322628283 + 322628284.

It is an arithmetic number, because the mean of its divisors is an integer number (322628284).

Almost surely, 2^645256567 is an apocalyptic number.

645256567 is a deficient number, since it is larger than the sum of its proper divisors (1).

645256567 is an equidigital number, since it uses as much as digits as its factorization.

645256567 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1512000, while the sum is 46.

The square root of 645256567 is about 25401.9008540700. The cubic root of 645256567 is about 864.1268063589.

The spelling of 645256567 in words is "six hundred forty-five million, two hundred fifty-six thousand, five hundred sixty-seven".