640743 has 8 divisors (see below), whose sum is σ = 874368. Its totient is φ = 417144.

The previous prime is 640741. The next prime is 640771. The reversal of 640743 is 347046.

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

It is not a de Polignac number, because 640743 - 2¹ = 640741 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640741) 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, 2355 + ... + 2612.

It is an arithmetic number, because the mean of its divisors is an integer number (109296).

2⁶⁴⁰⁷⁴³ is an apocalyptic number.

640743 is a deficient number, since it is larger than the sum of its proper divisors (233625).

640743 is a wasteful number, since it uses less digits than its factorization.

640743 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5013.

The product of its (nonzero) digits is 2016, while the sum is 24.

The square root of 640743 is about 800.4642403006. The cubic root of 640743 is about 86.2107235579.

Adding to 640743 its reverse (347046), we get a palindrome (987789).

The spelling of 640743 in words is "six hundred forty thousand, seven hundred forty-three".