645754321 has 2 divisors, whose sum is σ = 645754322. Its totient is φ = 645754320.

The previous prime is 645754289. The next prime is 645754331. The reversal of 645754321 is 123457546.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 640646721 + 5107600 = 25311^2 + 2260^2 .

It is a cyclic number.

It is not a de Polignac number, because 645754321 - 2⁵ = 645754289 is a prime.

It is not a weakly prime, because it can be changed into another prime (645754331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322877160 + 322877161.

It is an arithmetic number, because the mean of its divisors is an integer number (322877161).

Almost surely, 2^645754321 is an apocalyptic number.

It is an amenable number.

645754321 is a deficient number, since it is larger than the sum of its proper divisors (1).

645754321 is an equidigital number, since it uses as much as digits as its factorization.

645754321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 100800, while the sum is 37.

The square root of 645754321 is about 25411.6965391923. The cubic root of 645754321 is about 864.3489464316.

The spelling of 645754321 in words is "six hundred forty-five million, seven hundred fifty-four thousand, three hundred twenty-one".