1218838689 has 12 divisors (see below), whose sum is σ = 1766102676. Its totient is φ = 809993952.

The previous prime is 1218838667. The next prime is 1218838717. The reversal of 1218838689 is 9868388121.

1218838689 is a `hidden beast` number, since 1 + 2 + 188 + 386 + 89 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 146603664 + 1072235025 = 12108^2 + 32745^2 .

It is not a de Polignac number, because 1218838689 - 2⁸ = 1218838433 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1218838289) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 210754 + ... + 216459.

It is an arithmetic number, because the mean of its divisors is an integer number (147175223).

Almost surely, 2^1218838689 is an apocalyptic number.

It is an amenable number.

1218838689 is a deficient number, since it is larger than the sum of its proper divisors (547263987).

1218838689 is a wasteful number, since it uses less digits than its factorization.

1218838689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 427536 (or 427533 counting only the distinct ones).

The product of its digits is 1327104, while the sum is 54.

The square root of 1218838689 is about 34911.8703165557. The cubic root of 1218838689 is about 1068.1905800747.

The spelling of 1218838689 in words is "one billion, two hundred eighteen million, eight hundred thirty-eight thousand, six hundred eighty-nine".