643503 has 8 divisors (see below), whose sum is σ = 980608. Its totient is φ = 367704.

The previous prime is 643493. The next prime is 643507. The reversal of 643503 is 305346.

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

It is not a de Polignac number, because 643503 - 2⁶ = 643439 is a prime.

It is a super-2 number, since 2×643503² = 828192222018, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21), and also a Moran number because the ratio is a prime number: 30643 = 643503 / (6 + 4 + 3 + 5 + 0 + 3).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 643503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643507) 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, 15301 + ... + 15342.

It is an arithmetic number, because the mean of its divisors is an integer number (122576).

2⁶⁴³⁵⁰³ is an apocalyptic number.

643503 is a deficient number, since it is larger than the sum of its proper divisors (337105).

643503 is a wasteful number, since it uses less digits than its factorization.

643503 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30653.

The product of its (nonzero) digits is 1080, while the sum is 21.

The square root of 643503 is about 802.1863873191. The cubic root of 643503 is about 86.3343304579.

Adding to 643503 its reverse (305346), we get a palindrome (948849).

The spelling of 643503 in words is "six hundred forty-three thousand, five hundred three".