645258813 has 16 divisors (see below), whose sum is σ = 898352640. Its totient is φ = 411193904.

The previous prime is 645258781. The next prime is 645258833. The reversal of 645258813 is 318852546.

It is a cyclic number.

It is not a de Polignac number, because 645258813 - 2⁵ = 645258781 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645258833) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 167770 + ... + 171572.

It is an arithmetic number, because the mean of its divisors is an integer number (56147040).

Almost surely, 2^645258813 is an apocalyptic number.

It is an amenable number.

645258813 is a deficient number, since it is larger than the sum of its proper divisors (253093827).

645258813 is a wasteful number, since it uses less digits than its factorization.

645258813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6288.

The product of its digits is 230400, while the sum is 42.

The square root of 645258813 is about 25401.9450633214. The cubic root of 645258813 is about 864.1278089712.

The spelling of 645258813 in words is "six hundred forty-five million, two hundred fifty-eight thousand, eight hundred thirteen".