645907 has 2 divisors, whose sum is σ = 645908. Its totient is φ = 645906.

The previous prime is 645901. The next prime is 645937. The reversal of 645907 is 709546.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 645907 - 2¹¹ = 643859 is a prime.

It is not a weakly prime, because it can be changed into another prime (645901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322953 + 322954.

It is an arithmetic number, because the mean of its divisors is an integer number (322954).

2⁶⁴⁵⁹⁰⁷ is an apocalyptic number.

645907 is a deficient number, since it is larger than the sum of its proper divisors (1).

645907 is an equidigital number, since it uses as much as digits as its factorization.

645907 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7560, while the sum is 31.

The square root of 645907 is about 803.6833953741. The cubic root of 645907 is about 86.4417061879.

The spelling of 645907 in words is "six hundred forty-five thousand, nine hundred seven".