1321511311205 has 8 divisors (see below), whose sum is σ = 1597388855832. Its totient is φ = 1049492194048.

The previous prime is 1321511311201. The next prime is 1321511311243. The reversal of 1321511311205 is 5021131151231.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 74516988484 + 1246994322721 = 272978^2 + 1116689^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1321511311205 - 2² = 1321511311201 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1321511311201) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 964606112 + ... + 964607481.

It is an arithmetic number, because the mean of its divisors is an integer number (199673606979).

Almost surely, 2^{1321511311205} is an apocalyptic number.

It is an amenable number.

1321511311205 is a deficient number, since it is larger than the sum of its proper divisors (275877544627).

1321511311205 is a wasteful number, since it uses less digits than its factorization.

1321511311205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1929213735.

The product of its (nonzero) digits is 900, while the sum is 26.

Adding to 1321511311205 its reverse (5021131151231), we get a palindrome (6342642462436).

The spelling of 1321511311205 in words is "one trillion, three hundred twenty-one billion, five hundred eleven million, three hundred eleven thousand, two hundred five".