1320405565 has 8 divisors (see below), whose sum is σ = 1598509368. Its totient is φ = 1046976000.

The previous prime is 1320405503. The next prime is 1320405571. The reversal of 1320405565 is 5655040231.

1320405565 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 47485881 + 1272919684 = 6891^2 + 35678^2 .

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

It is not a de Polignac number, because 1320405565 - 2¹⁵ = 1320372797 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1167936 + ... + 1169065.

It is an arithmetic number, because the mean of its divisors is an integer number (199813671).

Almost surely, 2^1320405565 is an apocalyptic number.

It is an amenable number.

1320405565 is a deficient number, since it is larger than the sum of its proper divisors (278103803).

1320405565 is a wasteful number, since it uses less digits than its factorization.

1320405565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2337119.

The product of its (nonzero) digits is 18000, while the sum is 31.

The square root of 1320405565 is about 36337.3852251369. The cubic root of 1320405565 is about 1097.0736447184.

Adding to 1320405565 its reverse (5655040231), we get a palindrome (6975445796).

The spelling of 1320405565 in words is "one billion, three hundred twenty million, four hundred five thousand, five hundred sixty-five".