1221320218 has 8 divisors (see below), whose sum is σ = 1876662900. Its totient is φ = 595765920.

The previous prime is 1221320197. The next prime is 1221320227. The reversal of 1221320218 is 8120231221.

It can be written as a sum of positive squares in 2 ways, for example, as 1216405129 + 4915089 = 34877^2 + 2217^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7446993 + ... + 7447156.

Almost surely, 2^1221320218 is an apocalyptic number.

1221320218 is a deficient number, since it is larger than the sum of its proper divisors (655342682).

1221320218 is a wasteful number, since it uses less digits than its factorization.

1221320218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14894192.

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 1221320218 is about 34947.3921487713. The cubic root of 1221320218 is about 1068.9150262228.

Adding to 1221320218 its reverse (8120231221), we get a palindrome (9341551439).

The spelling of 1221320218 in words is "one billion, two hundred twenty-one million, three hundred twenty thousand, two hundred eighteen".