1218117511521 has 48 divisors (see below), whose sum is σ = 1803498582912. Its totient is φ = 792094464000.

The previous prime is 1218117511493. The next prime is 1218117511529. The reversal of 1218117511521 is 1251157118121.

1218117511521 is a `hidden beast` number, since 1 + 2 + 1 + 8 + 117 + 5 + 11 + 521 = 666.

It is not a de Polignac number, because 1218117511521 - 2²² = 1218113317217 is a prime.

It is a super-2 number, since 2×1218117511521² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1218117511529) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 18036306 + ... + 18103716.

It is an arithmetic number, because the mean of its divisors is an integer number (37572887144).

Almost surely, 2^{1218117511521} is an apocalyptic number.

It is an amenable number.

1218117511521 is a deficient number, since it is larger than the sum of its proper divisors (585381071391).

1218117511521 is a wasteful number, since it uses less digits than its factorization.

1218117511521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67814 (or 67811 counting only the distinct ones).

The product of its digits is 5600, while the sum is 36.

The spelling of 1218117511521 in words is "one trillion, two hundred eighteen billion, one hundred seventeen million, five hundred eleven thousand, five hundred twenty-one".