1218402909 has 6 divisors (see below), whose sum is σ = 1759915326. Its totient is φ = 812268600.

The previous prime is 1218402907. The next prime is 1218402919. The reversal of 1218402909 is 9092048121.

It can be written as a sum of positive squares in only one way, i.e., 1156340025 + 62062884 = 34005^2 + 7878^2 .

It is not a de Polignac number, because 1218402909 - 2¹ = 1218402907 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1218402907) 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 5 ways as a sum of consecutive naturals, for example, 67689042 + ... + 67689059.

It is an arithmetic number, because the mean of its divisors is an integer number (293319221).

Almost surely, 2^1218402909 is an apocalyptic number.

It is an amenable number.

1218402909 is a deficient number, since it is larger than the sum of its proper divisors (541512417).

1218402909 is a wasteful number, since it uses less digits than its factorization.

1218402909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135378107 (or 135378104 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 1218402909 is about 34905.6286148810. The cubic root of 1218402909 is about 1068.0632589934.

The spelling of 1218402909 in words is "one billion, two hundred eighteen million, four hundred two thousand, nine hundred nine".