640703 has 4 divisors (see below), whose sum is σ = 732240. Its totient is φ = 549168.

The previous prime is 640691. The next prime is 640727. The reversal of 640703 is 307046.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 307046 = 2 ⋅153523.

It is a cyclic number.

It is not a de Polignac number, because 640703 - 2⁴ = 640687 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 640703.

It is not an unprimeable number, because it can be changed into a prime (640733) 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 3 ways as a sum of consecutive naturals, for example, 45758 + ... + 45771.

It is an arithmetic number, because the mean of its divisors is an integer number (183060).

2⁶⁴⁰⁷⁰³ is an apocalyptic number.

640703 is a deficient number, since it is larger than the sum of its proper divisors (91537).

640703 is an equidigital number, since it uses as much as digits as its factorization.

640703 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91536.

The product of its (nonzero) digits is 504, while the sum is 20.

The square root of 640703 is about 800.4392544097. The cubic root of 640703 is about 86.2089295465.

Adding to 640703 its reverse (307046), we get a palindrome (947749).

The spelling of 640703 in words is "six hundred forty thousand, seven hundred three".