320821817 has 2 divisors, whose sum is σ = 320821818. Its totient is φ = 320821816.

The previous prime is 320821801. The next prime is 320821873. The reversal of 320821817 is 718128023.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 198697216 + 122124601 = 14096^2 + 11051^2 .

It is a cyclic number.

It is not a de Polignac number, because 320821817 - 2⁴ = 320821801 is a prime.

It is a super-3 number, since 3×320821817³ (a number of 26 digits) contains 333 as substring.

It is a Chen prime.

It is equal to p_17317265 and since 320821817 and 17317265 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (320821877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160410908 + 160410909.

It is an arithmetic number, because the mean of its divisors is an integer number (160410909).

Almost surely, 2^320821817 is an apocalyptic number.

It is an amenable number.

320821817 is a deficient number, since it is larger than the sum of its proper divisors (1).

320821817 is an equidigital number, since it uses as much as digits as its factorization.

320821817 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5376, while the sum is 32.

The square root of 320821817 is about 17911.4995742958. The cubic root of 320821817 is about 684.5754145068.

The spelling of 320821817 in words is "three hundred twenty million, eight hundred twenty-one thousand, eight hundred seventeen".