645043 has 8 divisors (see below), whose sum is σ = 754688. Its totient is φ = 539784.

The previous prime is 645041. The next prime is 645049. The reversal of 645043 is 340546.

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

It is not a de Polignac number, because 645043 - 2¹ = 645041 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645041) 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, 771 + ... + 1372.

It is an arithmetic number, because the mean of its divisors is an integer number (94336).

2⁶⁴⁵⁰⁴³ is an apocalyptic number.

645043 is a deficient number, since it is larger than the sum of its proper divisors (109645).

645043 is a wasteful number, since it uses less digits than its factorization.

645043 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2193.

The product of its (nonzero) digits is 1440, while the sum is 22.

The square root of 645043 is about 803.1456903950. The cubic root of 645043 is about 86.4031459617.

Adding to 645043 its reverse (340546), we get a palindrome (985589).

The spelling of 645043 in words is "six hundred forty-five thousand, forty-three".