640983 has 16 divisors (see below), whose sum is σ = 988416. Its totient is φ = 361920.

The previous prime is 640973. The next prime is 640993. The reversal of 640983 is 389046.

It is an interprime number because it is at equal distance from previous prime (640973) and next prime (640993).

It is not a de Polignac number, because 640983 - 2⁴ = 640967 is a prime.

640983 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 640983.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640933) 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 15 ways as a sum of consecutive naturals, for example, 2635 + ... + 2867.

It is an arithmetic number, because the mean of its divisors is an integer number (61776).

2⁶⁴⁰⁹⁸³ is an apocalyptic number.

640983 is a deficient number, since it is larger than the sum of its proper divisors (347433).

640983 is a wasteful number, since it uses less digits than its factorization.

640983 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 374.

The product of its (nonzero) digits is 5184, while the sum is 30.

The square root of 640983 is about 800.6141392706. The cubic root of 640983 is about 86.2214860586.

The spelling of 640983 in words is "six hundred forty thousand, nine hundred eighty-three".