1664411321 has 2 divisors, whose sum is σ = 1664411322. Its totient is φ = 1664411320.

The previous prime is 1664411279. The next prime is 1664411351. The reversal of 1664411321 is 1231144661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1525996096 + 138415225 = 39064^2 + 11765^2 .

It is a cyclic number.

It is not a de Polignac number, because 1664411321 - 2¹⁸ = 1664149177 is a prime.

It is not a weakly prime, because it can be changed into another prime (1664411351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832205660 + 832205661.

It is an arithmetic number, because the mean of its divisors is an integer number (832205661).

Almost surely, 2^1664411321 is an apocalyptic number.

It is an amenable number.

1664411321 is a deficient number, since it is larger than the sum of its proper divisors (1).

1664411321 is an equidigital number, since it uses as much as digits as its factorization.

1664411321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3456, while the sum is 29.

The square root of 1664411321 is about 40797.1974650220. The cubic root of 1664411321 is about 1185.0960584893.

Adding to 1664411321 its reverse (1231144661), we get a palindrome (2895555982).

The spelling of 1664411321 in words is "one billion, six hundred sixty-four million, four hundred eleven thousand, three hundred twenty-one".