645941 has 2 divisors, whose sum is σ = 645942. Its totient is φ = 645940.

The previous prime is 645937. The next prime is 645973. The reversal of 645941 is 149546.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 461041 + 184900 = 679^2 + 430^2 .

It is a cyclic number.

It is not a de Polignac number, because 645941 - 2² = 645937 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

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

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322970 + 322971.

It is an arithmetic number, because the mean of its divisors is an integer number (322971).

2⁶⁴⁵⁹⁴¹ is an apocalyptic number.

It is an amenable number.

645941 is a deficient number, since it is larger than the sum of its proper divisors (1).

645941 is an equidigital number, since it uses as much as digits as its factorization.

645941 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4320, while the sum is 29.

The square root of 645941 is about 803.7045477039. The cubic root of 645941 is about 86.4432229008.

The spelling of 645941 in words is "six hundred forty-five thousand, nine hundred forty-one".