645945373 has 2 divisors, whose sum is σ = 645945374. Its totient is φ = 645945372.

The previous prime is 645945367. The next prime is 645945401. The reversal of 645945373 is 373549546.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 359557444 + 286387929 = 18962^2 + 16923^2 .

It is a cyclic number.

It is not a de Polignac number, because 645945373 - 2⁵ = 645945341 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645945343) 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, 322972686 + 322972687.

It is an arithmetic number, because the mean of its divisors is an integer number (322972687).

Almost surely, 2^645945373 is an apocalyptic number.

It is an amenable number.

645945373 is a deficient number, since it is larger than the sum of its proper divisors (1).

645945373 is an equidigital number, since it uses as much as digits as its factorization.

645945373 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1360800, while the sum is 46.

The square root of 645945373 is about 25415.4553962741. The cubic root of 645945373 is about 864.4341797299.

The spelling of 645945373 in words is "six hundred forty-five million, nine hundred forty-five thousand, three hundred seventy-three".