640298 has 4 divisors (see below), whose sum is σ = 960450. Its totient is φ = 320148.

The previous prime is 640279. The next prime is 640303. The reversal of 640298 is 892046.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 628849 + 11449 = 793^2 + 107^2 .

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 640298.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 640298.

It is an unprimeable number.

640298 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160073 + ... + 160076.

2⁶⁴⁰²⁹⁸ is an apocalyptic number.

640298 is a deficient number, since it is larger than the sum of its proper divisors (320152).

640298 is a wasteful number, since it uses less digits than its factorization.

640298 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320151.

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 640298 is about 800.1862283244. The cubic root of 640298 is about 86.1907609745.

It can be divided in two parts, 6 and 40298, that added together give a palindrome (40304).

The spelling of 640298 in words is "six hundred forty thousand, two hundred ninety-eight".