640003 has 12 divisors (see below), whose sum is σ = 793488. Its totient is φ = 505440.

The previous prime is 639997. The next prime is 640007. The reversal of 640003 is 300046.

It is not a de Polignac number, because 640003 - 2⁹ = 639491 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640007) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 913 + ... + 1453.

It is an arithmetic number, because the mean of its divisors is an integer number (66124).

2⁶⁴⁰⁰⁰³ is an apocalyptic number.

640003 is a deficient number, since it is larger than the sum of its proper divisors (153485).

640003 is a wasteful number, since it uses less digits than its factorization.

640003 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 574 (or 561 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 13.

The square root of 640003 is about 800.0018749978. The cubic root of 640003 is about 86.1775222532.

Adding to 640003 its reverse (300046), we get a palindrome (940049).

The spelling of 640003 in words is "six hundred forty thousand, three".