1321220555 has 8 divisors (see below), whose sum is σ = 1595965344. Its totient is φ = 1049976000.

The previous prime is 1321220539. The next prime is 1321220573. The reversal of 1321220555 is 5550221231.

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

It is not a de Polignac number, because 1321220555 - 2⁴ = 1321220539 is a prime.

It is a Duffinian 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, 874226 + ... + 875735.

It is an arithmetic number, because the mean of its divisors is an integer number (199495668).

Almost surely, 2^1321220555 is an apocalyptic number.

1321220555 is a deficient number, since it is larger than the sum of its proper divisors (274744789).

1321220555 is a wasteful number, since it uses less digits than its factorization.

1321220555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1750117.

The product of its (nonzero) digits is 3000, while the sum is 26.

The square root of 1321220555 is about 36348.5977033503. The cubic root of 1321220555 is about 1097.2993127963.

Adding to 1321220555 its reverse (5550221231), we get a palindrome (6871441786).

The spelling of 1321220555 in words is "one billion, three hundred twenty-one million, two hundred twenty thousand, five hundred fifty-five".