320660821 has 4 divisors (see below), whose sum is σ = 345327052. Its totient is φ = 295994592.

The previous prime is 320660819. The next prime is 320660849. The reversal of 320660821 is 128066023.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 171479025 + 149181796 = 13095^2 + 12214^2 .

It is a cyclic number.

It is not a de Polignac number, because 320660821 - 2¹ = 320660819 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 320660821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (320661821) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12333096 + ... + 12333121.

It is an arithmetic number, because the mean of its divisors is an integer number (86331763).

Almost surely, 2^320660821 is an apocalyptic number.

It is an amenable number.

320660821 is a deficient number, since it is larger than the sum of its proper divisors (24666231).

320660821 is a wasteful number, since it uses less digits than its factorization.

320660821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24666230.

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 320660821 is about 17907.0048025905. The cubic root of 320660821 is about 684.4608832845.

The spelling of 320660821 in words is "three hundred twenty million, six hundred sixty thousand, eight hundred twenty-one".