320661 has 24 divisors (see below), whose sum is σ = 524160. Its totient is φ = 187200.

The previous prime is 320659. The next prime is 320669. The reversal of 320661 is 166023.

It is a happy number.

320661 is a `hidden beast` number, since 3 + 2 + 0 + 661 = 666.

It is not a de Polignac number, because 320661 - 2¹ = 320659 is a prime.

It is a plaindrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (320669) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4020 + ... + 4098.

It is an arithmetic number, because the mean of its divisors is an integer number (21840).

2³²⁰⁶⁶¹ is an apocalyptic number.

It is an amenable number.

320661 is a deficient number, since it is larger than the sum of its proper divisors (203499).

320661 is a wasteful number, since it uses less digits than its factorization.

320661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137 (or 134 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 320661 is about 566.2693705296. The cubic root of 320661 is about 68.4461010645.

Adding to 320661 its reverse (166023), we get a palindrome (486684).

The spelling of 320661 in words is "three hundred twenty thousand, six hundred sixty-one".