321675721 has 2 divisors, whose sum is σ = 321675722. Its totient is φ = 321675720.

The previous prime is 321675703. The next prime is 321675727. The reversal of 321675721 is 127576123.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 213744400 + 107931321 = 14620^2 + 10389^2 .

It is an emirp because it is prime and its reverse (127576123) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 321675721 - 2⁵ = 321675689 is a prime.

It is not a weakly prime, because it can be changed into another prime (321675727) 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, 160837860 + 160837861.

It is an arithmetic number, because the mean of its divisors is an integer number (160837861).

Almost surely, 2^321675721 is an apocalyptic number.

It is an amenable number.

321675721 is a deficient number, since it is larger than the sum of its proper divisors (1).

321675721 is an equidigital number, since it uses as much as digits as its factorization.

321675721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17640, while the sum is 34.

The square root of 321675721 is about 17935.3204877973. The cubic root of 321675721 is about 685.1822350672.

The spelling of 321675721 in words is "three hundred twenty-one million, six hundred seventy-five thousand, seven hundred twenty-one".