1320255666 has 64 divisors (see below), whose sum is σ = 3135749760. Its totient is φ = 410296320.

The previous prime is 1320255661. The next prime is 1320255707. The reversal of 1320255666 is 6665520231.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 1320255666.

It is not an unprimeable number, because it can be changed into a prime (1320255661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 91506 + ... + 104946.

It is an arithmetic number, because the mean of its divisors is an integer number (48996090).

Almost surely, 2^1320255666 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1320255666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1567874880).

1320255666 is an abundant number, since it is smaller than the sum of its proper divisors (1815494094).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1320255666 is a wasteful number, since it uses less digits than its factorization.

1320255666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13576 (or 13570 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 36.

The square root of 1320255666 is about 36335.3225663403. The cubic root of 1320255666 is about 1097.0321280637.

Adding to 1320255666 its reverse (6665520231), we get a palindrome (7985775897).

The spelling of 1320255666 in words is "one billion, three hundred twenty million, two hundred fifty-five thousand, six hundred sixty-six".