321663493 has 2 divisors, whose sum is σ = 321663494. Its totient is φ = 321663492.

The previous prime is 321663439. The next prime is 321663497. The reversal of 321663493 is 394366123.

Together with previous prime (321663439) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 268402689 + 53260804 = 16383^2 + 7298^2 .

It is an emirp because it is prime and its reverse (394366123) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-321663493 is a prime.

It is a super-2 number, since 2×321663493² = 206934805457922098, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (321663497) 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, 160831746 + 160831747.

It is an arithmetic number, because the mean of its divisors is an integer number (160831747).

Almost surely, 2^321663493 is an apocalyptic number.

It is an amenable number.

321663493 is a deficient number, since it is larger than the sum of its proper divisors (1).

321663493 is an equidigital number, since it uses as much as digits as its factorization.

321663493 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 69984, while the sum is 37.

The square root of 321663493 is about 17934.9795929630. The cubic root of 321663493 is about 685.1735529131.

The spelling of 321663493 in words is "three hundred twenty-one million, six hundred sixty-three thousand, four hundred ninety-three".