1321566655 has 12 divisors (see below), whose sum is σ = 1684656360. Its totient is φ = 995060864.

The previous prime is 1321566619. The next prime is 1321566671. The reversal of 1321566655 is 5566651231.

It is not a de Polignac number, because 1321566655 - 2¹⁵ = 1321533887 is a prime.

It is a congruent number.

It is an unprimeable number.

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 in 11 ways as a sum of consecutive naturals, for example, 455845 + ... + 458734.

It is an arithmetic number, because the mean of its divisors is an integer number (140388030).

Almost surely, 2^1321566655 is an apocalyptic number.

1321566655 is a deficient number, since it is larger than the sum of its proper divisors (363089705).

1321566655 is an equidigital number, since it uses as much as digits as its factorization.

1321566655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 914618 (or 914601 counting only the distinct ones).

The product of its digits is 162000, while the sum is 40.

The square root of 1321566655 is about 36353.3582355193. The cubic root of 1321566655 is about 1097.3951186868.

The spelling of 1321566655 in words is "one billion, three hundred twenty-one million, five hundred sixty-six thousand, six hundred fifty-five".