1166121681 has 16 divisors (see below), whose sum is σ = 1663268544. Its totient is φ = 724137984.

The previous prime is 1166121611. The next prime is 1166121701. The reversal of 1166121681 is 1861216611.

It is not a de Polignac number, because 1166121681 - 2⁷ = 1166121553 is a prime.

It is a super-2 number, since 2×1166121681² = 2719679549796531522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1166121611) 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 15 ways as a sum of consecutive naturals, for example, 112915 + ... + 122808.

It is an arithmetic number, because the mean of its divisors is an integer number (103954284).

Almost surely, 2^1166121681 is an apocalyptic number.

It is an amenable number.

1166121681 is a deficient number, since it is larger than the sum of its proper divisors (497146863).

1166121681 is a wasteful number, since it uses less digits than its factorization.

1166121681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 235840.

The product of its digits is 3456, while the sum is 33.

The square root of 1166121681 is about 34148.5238480377. The cubic root of 1166121681 is about 1052.5626538194.

The spelling of 1166121681 in words is "one billion, one hundred sixty-six million, one hundred twenty-one thousand, six hundred eighty-one".