640273 has 4 divisors (see below), whose sum is σ = 644148. Its totient is φ = 636400.

The previous prime is 640267. The next prime is 640279. The reversal of 640273 is 372046.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 372046 = 2 ⋅186023.

It is an interprime number because it is at equal distance from previous prime (640267) and next prime (640279).

It can be written as a sum of positive squares in 2 ways, for example, as 439569 + 200704 = 663^2 + 448^2 .

It is a cyclic number.

It is not a de Polignac number, because 640273 - 2¹³ = 632081 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640279) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1678 + ... + 2023.

It is an arithmetic number, because the mean of its divisors is an integer number (161037).

2⁶⁴⁰²⁷³ is an apocalyptic number.

It is an amenable number.

640273 is a deficient number, since it is larger than the sum of its proper divisors (3875).

640273 is a wasteful number, since it uses less digits than its factorization.

640273 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3874.

The product of its (nonzero) digits is 1008, while the sum is 22.

The square root of 640273 is about 800.1706068083. The cubic root of 640273 is about 86.1896392067.

The spelling of 640273 in words is "six hundred forty thousand, two hundred seventy-three".