641845 has 8 divisors (see below), whose sum is σ = 776664. Its totient is φ = 509184.

The previous prime is 641843. The next prime is 641863. The reversal of 641845 is 548146.

641845 = 566² + 567².

It can be written as a sum of positive squares in 4 ways, for example, as 5041 + 636804 = 71^2 + 798^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 641845 - 2¹ = 641843 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 217 + ... + 1153.

It is an arithmetic number, because the mean of its divisors is an integer number (97083).

2⁶⁴¹⁸⁴⁵ is an apocalyptic number.

641845 is the 567-th centered square number.

It is an amenable number.

641845 is a deficient number, since it is larger than the sum of its proper divisors (134819).

641845 is a wasteful number, since it uses less digits than its factorization.

641845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1079.

The product of its digits is 3840, while the sum is 28.

The square root of 641845 is about 801.1522951350. The cubic root of 641845 is about 86.2601192356.

The spelling of 641845 in words is "six hundred forty-one thousand, eight hundred forty-five".