645611 has 2 divisors, whose sum is σ = 645612. Its totient is φ = 645610.

The previous prime is 645599. The next prime is 645629. The reversal of 645611 is 116546.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645611 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (645641) 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, 322805 + 322806.

It is an arithmetic number, because the mean of its divisors is an integer number (322806).

2⁶⁴⁵⁶¹¹ is an apocalyptic number.

645611 is a deficient number, since it is larger than the sum of its proper divisors (1).

645611 is an equidigital number, since it uses as much as digits as its factorization.

645611 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 720, while the sum is 23.

The square root of 645611 is about 803.4992221527. The cubic root of 645611 is about 86.4284996145.

The spelling of 645611 in words is "six hundred forty-five thousand, six hundred eleven".