646841 has 4 divisors (see below), whose sum is σ = 696612. Its totient is φ = 597072.

The previous prime is 646837. The next prime is 646843. The reversal of 646841 is 148646.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 148646 = 2 ⋅74323.

It can be written as a sum of positive squares in 2 ways, for example, as 40000 + 606841 = 200^2 + 779^2 .

It is a cyclic number.

It is not a de Polignac number, because 646841 - 2² = 646837 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (646843) 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 3 ways as a sum of consecutive naturals, for example, 24866 + ... + 24891.

It is an arithmetic number, because the mean of its divisors is an integer number (174153).

2⁶⁴⁶⁸⁴¹ is an apocalyptic number.

It is an amenable number.

646841 is a deficient number, since it is larger than the sum of its proper divisors (49771).

646841 is a wasteful number, since it uses less digits than its factorization.

646841 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49770.

The product of its digits is 4608, while the sum is 29.

The square root of 646841 is about 804.2642600539. The cubic root of 646841 is about 86.4833518474.

The spelling of 646841 in words is "six hundred forty-six thousand, eight hundred forty-one".