1218113557 has 4 divisors (see below), whose sum is σ = 1271075040. Its totient is φ = 1165152076.

The previous prime is 1218113549. The next prime is 1218113581. The reversal of 1218113557 is 7553118121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 7553118121 = 29 ⋅260452349.

It is a cyclic number.

It is not a de Polignac number, because 1218113557 - 2³ = 1218113549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1218113357) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26480707 + ... + 26480752.

It is an arithmetic number, because the mean of its divisors is an integer number (317768760).

Almost surely, 2^1218113557 is an apocalyptic number.

It is an amenable number.

1218113557 is a deficient number, since it is larger than the sum of its proper divisors (52961483).

1218113557 is an equidigital number, since it uses as much as digits as its factorization.

1218113557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52961482.

The product of its digits is 8400, while the sum is 34.

The square root of 1218113557 is about 34901.4835931082. The cubic root of 1218113557 is about 1067.9787027530.

The spelling of 1218113557 in words is "one billion, two hundred eighteen million, one hundred thirteen thousand, five hundred fifty-seven".