645407239 has 2 divisors, whose sum is σ = 645407240. Its totient is φ = 645407238.

The previous prime is 645407237. The next prime is 645407291. The reversal of 645407239 is 932704546.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 645407239 - 2¹ = 645407237 is a prime.

Together with 645407237, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645407237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322703619 + 322703620.

It is an arithmetic number, because the mean of its divisors is an integer number (322703620).

Almost surely, 2^645407239 is an apocalyptic number.

645407239 is a deficient number, since it is larger than the sum of its proper divisors (1).

645407239 is an equidigital number, since it uses as much as digits as its factorization.

645407239 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 181440, while the sum is 40.

The square root of 645407239 is about 25404.8664432624. The cubic root of 645407239 is about 864.1940610438.

The spelling of 645407239 in words is "six hundred forty-five million, four hundred seven thousand, two hundred thirty-nine".