645003 has 10 divisors (see below), whose sum is σ = 963644. Its totient is φ = 429948.

The previous prime is 644999. The next prime is 645011. The reversal of 645003 is 300546.

It is a happy number.

It is not a de Polignac number, because 645003 - 2² = 644999 is a prime.

It is a Duffinian number.

645003 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (645013) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 3901 + ... + 4062.

2⁶⁴⁵⁰⁰³ is an apocalyptic number.

645003 is a deficient number, since it is larger than the sum of its proper divisors (318641).

645003 is an equidigital number, since it uses as much as digits as its factorization.

645003 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7975 (or 7966 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 18.

The square root of 645003 is about 803.1207879267. The cubic root of 645003 is about 86.4013599323.

Adding to 645003 its reverse (300546), we get a palindrome (945549).

The spelling of 645003 in words is "six hundred forty-five thousand, three".