645009 has 8 divisors (see below), whose sum is σ = 873120. Its totient is φ = 423456.

The previous prime is 644999. The next prime is 645011. The reversal of 645009 is 900546.

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

It is not a de Polignac number, because 645009 - 2⁵ = 644977 is a prime.

It is a super-2 number, since 2×645009² = 832073220162, which contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 645009.

It is not an unprimeable number, because it can be changed into a prime (645019) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1404 + ... + 1805.

It is an arithmetic number, because the mean of its divisors is an integer number (109140).

2⁶⁴⁵⁰⁰⁹ is an apocalyptic number.

It is an amenable number.

645009 is a deficient number, since it is larger than the sum of its proper divisors (228111).

645009 is a wasteful number, since it uses less digits than its factorization.

645009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3279.

The product of its (nonzero) digits is 1080, while the sum is 24.

The square root of 645009 is about 803.1245233462. The cubic root of 645009 is about 86.4016278414.

The spelling of 645009 in words is "six hundred forty-five thousand, nine".