321553 has 2 divisors, whose sum is σ = 321554. Its totient is φ = 321552.

The previous prime is 321547. The next prime is 321569. The reversal of 321553 is 355123.

It is the 232-nd star number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 321489 + 64 = 567^2 + 8^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-321553 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 321553.

It is not a weakly prime, because it can be changed into another prime (321593) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160776 + 160777.

It is an arithmetic number, because the mean of its divisors is an integer number (160777).

2³²¹⁵⁵³ is an apocalyptic number.

It is an amenable number.

321553 is a deficient number, since it is larger than the sum of its proper divisors (1).

321553 is an equidigital number, since it uses as much as digits as its factorization.

321553 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 450, while the sum is 19.

The square root of 321553 is about 567.0564345813. The cubic root of 321553 is about 68.5095090427.

Adding to 321553 its product of digits (450), we get a triangular number (322003 = T₈₀₂).

Adding to 321553 its reverse (355123), we get a palindrome (676676).

The spelling of 321553 in words is "three hundred twenty-one thousand, five hundred fifty-three".