645120653 has 2 divisors, whose sum is σ = 645120654. Its totient is φ = 645120652.

The previous prime is 645120647. The next prime is 645120667. The reversal of 645120653 is 356021546.

645120653 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., 556346569 + 88774084 = 23587^2 + 9422^2 .

It is a cyclic number.

It is not a de Polignac number, because 645120653 - 2⁶ = 645120589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645120253) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322560326 + 322560327.

It is an arithmetic number, because the mean of its divisors is an integer number (322560327).

Almost surely, 2^645120653 is an apocalyptic number.

It is an amenable number.

645120653 is a deficient number, since it is larger than the sum of its proper divisors (1).

645120653 is an equidigital number, since it uses as much as digits as its factorization.

645120653 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 21600, while the sum is 32.

The square root of 645120653 is about 25399.2254409460. The cubic root of 645120653 is about 864.0661301442.

The spelling of 645120653 in words is "six hundred forty-five million, one hundred twenty thousand, six hundred fifty-three".