640353 has 8 divisors (see below), whose sum is σ = 975808. Its totient is φ = 365904.

The previous prime is 640333. The next prime is 640363. The reversal of 640353 is 353046.

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

It is not a de Polignac number, because 640353 - 2¹⁰ = 639329 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21), and also a Moran number because the ratio is a prime number: 30493 = 640353 / (6 + 4 + 0 + 3 + 5 + 3).

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (640303) 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, 15226 + ... + 15267.

It is an arithmetic number, because the mean of its divisors is an integer number (121976).

2⁶⁴⁰³⁵³ is an apocalyptic number.

It is an amenable number.

640353 is a deficient number, since it is larger than the sum of its proper divisors (335455).

640353 is a wasteful number, since it uses less digits than its factorization.

640353 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30503.

The product of its (nonzero) digits is 1080, while the sum is 21.

The square root of 640353 is about 800.2205945863. The cubic root of 640353 is about 86.1932287610.

Adding to 640353 its reverse (353046), we get a palindrome (993399).

The spelling of 640353 in words is "six hundred forty thousand, three hundred fifty-three".