645441643 has 8 divisors (see below), whose sum is σ = 804706560. Its totient is φ = 502941480.

The previous prime is 645441631. The next prime is 645441659. The reversal of 645441643 is 346144546.

645441643 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645441643 is a prime.

It is not an unprimeable number, because it can be changed into a prime (645441443) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4191103 + ... + 4191256.

It is an arithmetic number, because the mean of its divisors is an integer number (100588320).

Almost surely, 2^645441643 is an apocalyptic number.

645441643 is a deficient number, since it is larger than the sum of its proper divisors (159264917).

645441643 is a wasteful number, since it uses less digits than its factorization.

645441643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8382377.

The product of its digits is 138240, while the sum is 37.

The square root of 645441643 is about 25405.5435486037. The cubic root of 645441643 is about 864.2094163122.

The spelling of 645441643 in words is "six hundred forty-five million, four hundred forty-one thousand, six hundred forty-three".