1218561205 has 16 divisors (see below), whose sum is σ = 1499710464. Its totient is φ = 949947520.

The previous prime is 1218561203. The next prime is 1218561217. The reversal of 1218561205 is 5021658121.

It is not a de Polignac number, because 1218561205 - 2¹ = 1218561203 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1218561203) by changing a digit.

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, 198492 + ... + 204538.

It is an arithmetic number, because the mean of its divisors is an integer number (93731904).

Almost surely, 2^1218561205 is an apocalyptic number.

It is an amenable number.

1218561205 is a deficient number, since it is larger than the sum of its proper divisors (281149259).

1218561205 is an equidigital number, since it uses as much as digits as its factorization.

1218561205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7076.

The product of its (nonzero) digits is 4800, while the sum is 31.

The square root of 1218561205 is about 34907.8960265439. The cubic root of 1218561205 is about 1068.1095115696.

The spelling of 1218561205 in words is "one billion, two hundred eighteen million, five hundred sixty-one thousand, two hundred five".