641805 has 8 divisors (see below), whose sum is σ = 1026912. Its totient is φ = 342288.

The previous prime is 641803. The next prime is 641813. The reversal of 641805 is 508146.

641805 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 641805 - 2¹ = 641803 is a prime.

641805 is a lucky number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 641805.

It is not an unprimeable number, because it can be changed into a prime (641803) 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, 21379 + ... + 21408.

It is an arithmetic number, because the mean of its divisors is an integer number (128364).

2⁶⁴¹⁸⁰⁵ is an apocalyptic number.

It is an amenable number.

641805 is a deficient number, since it is larger than the sum of its proper divisors (385107).

641805 is a wasteful number, since it uses less digits than its factorization.

641805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42795.

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 641805 is about 801.1273307034. The cubic root of 641805 is about 86.2583272783.

The spelling of 641805 in words is "six hundred forty-one thousand, eight hundred five".