645664853 has 8 divisors (see below), whose sum is σ = 652027200. Its totient is φ = 639334080.

The previous prime is 645664849. The next prime is 645664871. The reversal of 645664853 is 358466546.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 645664853 - 2² = 645664849 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 645664798 and 645664807.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645664753) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34301 + ... + 49677.

It is an arithmetic number, because the mean of its divisors is an integer number (81503400).

Almost surely, 2^645664853 is an apocalyptic number.

It is an amenable number.

645664853 is a deficient number, since it is larger than the sum of its proper divisors (6362347).

645664853 is a wasteful number, since it uses less digits than its factorization.

645664853 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15787.

The product of its digits is 2073600, while the sum is 47.

The square root of 645664853 is about 25409.9361077512. The cubic root of 645664853 is about 864.3090266351.

The spelling of 645664853 in words is "six hundred forty-five million, six hundred sixty-four thousand, eight hundred fifty-three".