1216526121 has 20 divisors (see below), whose sum is σ = 1834276752. Its totient is φ = 803432088.

The previous prime is 1216526117. The next prime is 1216526153. The reversal of 1216526121 is 1216256121.

1216526121 is a `hidden beast` number, since 1 + 2 + 1 + 652 + 6 + 1 + 2 + 1 = 666.

It is not a de Polignac number, because 1216526121 - 2² = 1216526117 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (1216526221) 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 19 ways as a sum of consecutive naturals, for example, 61515 + ... + 78848.

Almost surely, 2^1216526121 is an apocalyptic number.

It is an amenable number.

1216526121 is a deficient number, since it is larger than the sum of its proper divisors (617750631).

1216526121 is a wasteful number, since it uses less digits than its factorization.

1216526121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140482 (or 140473 counting only the distinct ones).

The product of its digits is 1440, while the sum is 27.

The square root of 1216526121 is about 34878.7345097267. The cubic root of 1216526121 is about 1067.5145739317.

The spelling of 1216526121 in words is "one billion, two hundred sixteen million, five hundred twenty-six thousand, one hundred twenty-one".