1218920305 has 16 divisors (see below), whose sum is σ = 1527384960. Its totient is φ = 932076288.

The previous prime is 1218920303. The next prime is 1218920323. The reversal of 1218920305 is 5030298121.

1218920305 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1218920305 - 2¹ = 1218920303 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1218920303) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 212566 + ... + 218224.

It is an arithmetic number, because the mean of its divisors is an integer number (95461560).

Almost surely, 2^1218920305 is an apocalyptic number.

It is an amenable number.

1218920305 is a deficient number, since it is larger than the sum of its proper divisors (308464655).

1218920305 is a wasteful number, since it uses less digits than its factorization.

1218920305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7560.

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 1218920305 is about 34913.0391830903. The cubic root of 1218920305 is about 1068.2144223045.

The spelling of 1218920305 in words is "one billion, two hundred eighteen million, nine hundred twenty thousand, three hundred five".