1218391168 has 16 divisors (see below), whose sum is σ = 2427263910. Its totient is φ = 609195520.

The previous prime is 1218391159. The next prime is 1218391177. The reversal of 1218391168 is 8611938121.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1218391159) and next prime (1218391177).

It can be written as a sum of positive squares in only one way, i.e., 1216056384 + 2334784 = 34872^2 + 1528^2 .

It is a tau number, because it is divible by the number of its divisors (16).

It is a hoax number, since the sum of its digits (40) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 1218391168.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4759213 + ... + 4759468.

Almost surely, 2^1218391168 is an apocalyptic number.

It is an amenable number.

1218391168 is a deficient number, since it is larger than the sum of its proper divisors (1208872742).

1218391168 is an frugal number, since it uses more digits than its factorization.

1218391168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9518695 (or 9518683 counting only the distinct ones).

The product of its digits is 20736, while the sum is 40.

The square root of 1218391168 is about 34905.4604324309. The cubic root of 1218391168 is about 1068.0598282260.

The spelling of 1218391168 in words is "one billion, two hundred eighteen million, three hundred ninety-one thousand, one hundred sixty-eight".