320813021 has 4 divisors (see below), whose sum is σ = 320938044. Its totient is φ = 320688000.

The previous prime is 320812991. The next prime is 320813033. The reversal of 320813021 is 120318023.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120318023 = 7 ⋅17188289.

It can be written as a sum of positive squares in 2 ways, for example, as 130759225 + 190053796 = 11435^2 + 13786^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-320813021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 320812984 and 320813002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (320813041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 58580 + ... + 63821.

It is an arithmetic number, because the mean of its divisors is an integer number (80234511).

Almost surely, 2^320813021 is an apocalyptic number.

It is an amenable number.

320813021 is a deficient number, since it is larger than the sum of its proper divisors (125023).

320813021 is a wasteful number, since it uses less digits than its factorization.

320813021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125022.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 320813021 is about 17911.2540320325. The cubic root of 320813021 is about 684.5691580948.

The spelling of 320813021 in words is "three hundred twenty million, eight hundred thirteen thousand, twenty-one".