641005 has 4 divisors (see below), whose sum is σ = 769212. Its totient is φ = 512800.

The previous prime is 640993. The next prime is 641051. The reversal of 641005 is 500146.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 500146 = 2 ⋅250073.

It can be written as a sum of positive squares in 2 ways, for example, as 381924 + 259081 = 618^2 + 509^2 .

It is not a de Polignac number, because 641005 - 2⁵ = 640973 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 641005.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 64096 + ... + 64105.

It is an arithmetic number, because the mean of its divisors is an integer number (192303).

2⁶⁴¹⁰⁰⁵ is an apocalyptic number.

It is an amenable number.

641005 is a deficient number, since it is larger than the sum of its proper divisors (128207).

641005 is a wasteful number, since it uses less digits than its factorization.

641005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128206.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 641005 is about 800.6278786053. The cubic root of 641005 is about 86.2224724867. Note that the first 3 decimals are identical.

The spelling of 641005 in words is "six hundred forty-one thousand, five".