1321185521 has 2 divisors, whose sum is σ = 1321185522. Its totient is φ = 1321185520.

The previous prime is 1321185499. The next prime is 1321185589. The reversal of 1321185521 is 1255811231.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1222481296 + 98704225 = 34964^2 + 9935^2 .

It is a cyclic number.

It is not a de Polignac number, because 1321185521 - 2⁶ = 1321185457 is a prime.

It is not a weakly prime, because it can be changed into another prime (1321185721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 660592760 + 660592761.

It is an arithmetic number, because the mean of its divisors is an integer number (660592761).

Almost surely, 2^1321185521 is an apocalyptic number.

It is an amenable number.

1321185521 is a deficient number, since it is larger than the sum of its proper divisors (1).

1321185521 is an equidigital number, since it uses as much as digits as its factorization.

1321185521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2400, while the sum is 29.

The square root of 1321185521 is about 36348.1157833525. The cubic root of 1321185521 is about 1097.2896139049.

Adding to 1321185521 its reverse (1255811231), we get a palindrome (2576996752).

The spelling of 1321185521 in words is "one billion, three hundred twenty-one million, one hundred eighty-five thousand, five hundred twenty-one".