1218449157138 has 48 divisors (see below), whose sum is σ = 2642393748696. Its totient is φ = 405777496320.

The previous prime is 1218449157109. The next prime is 1218449157197. The reversal of 1218449157138 is 8317519448121.

1218449157138 is a `hidden beast` number, since 1 + 2 + 1 + 84 + 491 + 5 + 71 + 3 + 8 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 1209157546689 + 9291610449 = 1099617^2 + 96393^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 182919528 + ... + 182926188.

Almost surely, 2^{1218449157138} is an apocalyptic number.

1218449157138 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1218449157138 is an abundant number, since it is smaller than the sum of its proper divisors (1423944591558).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1218449157138 is a wasteful number, since it uses less digits than its factorization.

1218449157138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14459 (or 14456 counting only the distinct ones).

The product of its digits is 1935360, while the sum is 54.

The spelling of 1218449157138 in words is "one trillion, two hundred eighteen billion, four hundred forty-nine million, one hundred fifty-seven thousand, one hundred thirty-eight".