645673027 has 2 divisors, whose sum is σ = 645673028. Its totient is φ = 645673026.

The previous prime is 645673013. The next prime is 645673069. The reversal of 645673027 is 720376546.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 645673027 - 2¹⁹ = 645148739 is a prime.

It is not a weakly prime, because it can be changed into another prime (645673087) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322836513 + 322836514.

It is an arithmetic number, because the mean of its divisors is an integer number (322836514).

Almost surely, 2^645673027 is an apocalyptic number.

645673027 is a deficient number, since it is larger than the sum of its proper divisors (1).

645673027 is an equidigital number, since it uses as much as digits as its factorization.

645673027 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 211680, while the sum is 40.

The square root of 645673027 is about 25410.0969498347. The cubic root of 645673027 is about 864.3126739516.

The spelling of 645673027 in words is "six hundred forty-five million, six hundred seventy-three thousand, twenty-seven".