1216220305 has 16 divisors (see below), whose sum is σ = 1537905600. Its totient is φ = 920790720.

The previous prime is 1216220297. The next prime is 1216220311. The reversal of 1216220305 is 5030226121.

It is not a de Polignac number, because 1216220305 - 2³ = 1216220297 is a prime.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 90726 + ... + 103264.

It is an arithmetic number, because the mean of its divisors is an integer number (96119100).

Almost surely, 2^1216220305 is an apocalyptic number.

It is an amenable number.

1216220305 is a deficient number, since it is larger than the sum of its proper divisors (321685295).

1216220305 is a wasteful number, since it uses less digits than its factorization.

1216220305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13584.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 1216220305 is about 34874.3502448433. The cubic root of 1216220305 is about 1067.4251141738.

Adding to 1216220305 its reverse (5030226121), we get a palindrome (6246446426).

The spelling of 1216220305 in words is "one billion, two hundred sixteen million, two hundred twenty thousand, three hundred five".