1218162809 has 2 divisors, whose sum is σ = 1218162810. Its totient is φ = 1218162808.

The previous prime is 1218162739. The next prime is 1218162811. The reversal of 1218162809 is 9082618121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 850597225 + 367565584 = 29165^2 + 19172^2 .

It is a cyclic number.

It is not a de Polignac number, because 1218162809 - 2²⁸ = 949727353 is a prime.

Together with 1218162811, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1218162839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 609081404 + 609081405.

It is an arithmetic number, because the mean of its divisors is an integer number (609081405).

Almost surely, 2^1218162809 is an apocalyptic number.

It is an amenable number.

1218162809 is a deficient number, since it is larger than the sum of its proper divisors (1).

1218162809 is an equidigital number, since it uses as much as digits as its factorization.

1218162809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13824, while the sum is 38.

The square root of 1218162809 is about 34902.1891720276. The cubic root of 1218162809 is about 1067.9930964242.

The spelling of 1218162809 in words is "one billion, two hundred eighteen million, one hundred sixty-two thousand, eight hundred nine".