1321728164 has 6 divisors (see below), whose sum is σ = 2313024294. Its totient is φ = 660864080.

The previous prime is 1321728101. The next prime is 1321728167. The reversal of 1321728164 is 4618271231.

It can be written as a sum of positive squares in only one way, i.e., 1278062500 + 43665664 = 35750^2 + 6608^2 .

It is not an unprimeable number, because it can be changed into a prime (1321728167) 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, 165216017 + ... + 165216024.

It is an arithmetic number, because the mean of its divisors is an integer number (385504049).

Almost surely, 2^1321728164 is an apocalyptic number.

It is an amenable number.

1321728164 is a deficient number, since it is larger than the sum of its proper divisors (991296130).

1321728164 is a wasteful number, since it uses less digits than its factorization.

1321728164 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330432045 (or 330432043 counting only the distinct ones).

The product of its digits is 16128, while the sum is 35.

The square root of 1321728164 is about 36355.5795442735. The cubic root of 1321728164 is about 1097.4398211789.

Adding to 1321728164 its reverse (4618271231), we get a palindrome (5939999395).

The spelling of 1321728164 in words is "one billion, three hundred twenty-one million, seven hundred twenty-eight thousand, one hundred sixty-four".