645449957 has 2 divisors, whose sum is σ = 645449958. Its totient is φ = 645449956.

The previous prime is 645449947. The next prime is 645450019. The reversal of 645449957 is 759944546.

645449957 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 371679841 + 273770116 = 19279^2 + 16546^2 .

It is a cyclic number.

It is not a de Polignac number, because 645449957 - 2²⁸ = 377014501 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 645449899 and 645449908.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645449947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322724978 + 322724979.

It is an arithmetic number, because the mean of its divisors is an integer number (322724979).

Almost surely, 2^645449957 is an apocalyptic number.

It is an amenable number.

645449957 is a deficient number, since it is larger than the sum of its proper divisors (1).

645449957 is an equidigital number, since it uses as much as digits as its factorization.

645449957 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5443200, while the sum is 53.

The square root of 645449957 is about 25405.7071737828. The cubic root of 645449957 is about 864.2131269530.

The spelling of 645449957 in words is "six hundred forty-five million, four hundred forty-nine thousand, nine hundred fifty-seven".