320023721 has 2 divisors, whose sum is σ = 320023722. Its totient is φ = 320023720.

The previous prime is 320023703. The next prime is 320023727. The reversal of 320023721 is 127320023.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 177555625 + 142468096 = 13325^2 + 11936^2 .

It is an emirp because it is prime and its reverse (127320023) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 320023721 - 2¹⁰ = 320022697 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 320023693 and 320023702.

It is not a weakly prime, because it can be changed into another prime (320023727) 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 as a sum of consecutive naturals, namely, 160011860 + 160011861.

It is an arithmetic number, because the mean of its divisors is an integer number (160011861).

Almost surely, 2^320023721 is an apocalyptic number.

It is an amenable number.

320023721 is a deficient number, since it is larger than the sum of its proper divisors (1).

320023721 is an equidigital number, since it uses as much as digits as its factorization.

320023721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 504, while the sum is 20.

The square root of 320023721 is about 17889.2068298178. The cubic root of 320023721 is about 684.0072792278.

Adding to 320023721 its reverse (127320023), we get a palindrome (447343744).

The spelling of 320023721 in words is "three hundred twenty million, twenty-three thousand, seven hundred twenty-one".