321021989 has 2 divisors, whose sum is σ = 321021990. Its totient is φ = 321021988.

The previous prime is 321021977. The next prime is 321022003. The reversal of 321021989 is 989120123.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 320589025 + 432964 = 17905^2 + 658^2 .

It is a cyclic number.

It is not a de Polignac number, because 321021989 - 2⁴ = 321021973 is a prime.

It is a super-2 number, since 2×321021989² = 206110234843032242, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (321021949) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160510994 + 160510995.

It is an arithmetic number, because the mean of its divisors is an integer number (160510995).

Almost surely, 2^321021989 is an apocalyptic number.

It is an amenable number.

321021989 is a deficient number, since it is larger than the sum of its proper divisors (1).

321021989 is an equidigital number, since it uses as much as digits as its factorization.

321021989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7776, while the sum is 35.

The square root of 321021989 is about 17917.0865098096. The cubic root of 321021989 is about 684.7177617877.

The spelling of 321021989 in words is "three hundred twenty-one million, twenty-one thousand, nine hundred eighty-nine".