1321541021 has 2 divisors, whose sum is σ = 1321541022. Its totient is φ = 1321541020.

The previous prime is 1321541017. The next prime is 1321541041. The reversal of 1321541021 is 1201451231.

It is an a-pointer prime, because the next prime (1321541041) can be obtained adding 1321541021 to its sum of digits (20).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 735223225 + 586317796 = 27115^2 + 24214^2 .

It is a cyclic number.

It is not a de Polignac number, because 1321541021 - 2² = 1321541017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1321540984 and 1321541002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1321541041) 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, 660770510 + 660770511.

It is an arithmetic number, because the mean of its divisors is an integer number (660770511).

Almost surely, 2^1321541021 is an apocalyptic number.

It is an amenable number.

1321541021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1321541021 is an equidigital number, since it uses as much as digits as its factorization.

1321541021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 1321541021 is about 36353.0056666571. The cubic root of 1321541021 is about 1097.3880233685.

Adding to 1321541021 its reverse (1201451231), we get a palindrome (2522992252).

The spelling of 1321541021 in words is "one billion, three hundred twenty-one million, five hundred forty-one thousand, twenty-one".