1321205305 has 16 divisors (see below), whose sum is σ = 1814952960. Its totient is φ = 904462272.

The previous prime is 1321205251. The next prime is 1321205309. The reversal of 1321205305 is 5035021231.

It is not a de Polignac number, because 1321205305 - 2⁷ = 1321205177 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1321205309) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9850 + ... + 52339.

It is an arithmetic number, because the mean of its divisors is an integer number (113434560).

Almost surely, 2^1321205305 is an apocalyptic number.

It is an amenable number.

1321205305 is a deficient number, since it is larger than the sum of its proper divisors (493747655).

1321205305 is an equidigital number, since it uses as much as digits as its factorization.

1321205305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62808.

The product of its (nonzero) digits is 900, while the sum is 22.

The square root of 1321205305 is about 36348.3879284900. The cubic root of 1321205305 is about 1097.2950909730.

Adding to 1321205305 its reverse (5035021231), we get a palindrome (6356226536).

The spelling of 1321205305 in words is "one billion, three hundred twenty-one million, two hundred five thousand, three hundred five".