1116691981 has 4 divisors (see below), whose sum is σ = 1118697372. Its totient is φ = 1114686592.

The previous prime is 1116691967. The next prime is 1116691987. The reversal of 1116691981 is 1891966111.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1891966111 = 7 ⋅270280873.

It can be written as a sum of positive squares in 2 ways, for example, as 278589481 + 838102500 = 16691^2 + 28950^2 .

It is a cyclic number.

It is not a de Polignac number, because 1116691981 - 2⁷ = 1116691853 is a prime.

It is a super-2 number, since 2×1116691981² = 2494001960859408722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1116691987) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1001860 + ... + 1002973.

It is an arithmetic number, because the mean of its divisors is an integer number (279674343).

Almost surely, 2^1116691981 is an apocalyptic number.

It is an amenable number.

1116691981 is a deficient number, since it is larger than the sum of its proper divisors (2005391).

1116691981 is an equidigital number, since it uses as much as digits as its factorization.

1116691981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2005390.

The product of its digits is 23328, while the sum is 43.

The square root of 1116691981 is about 33416.9415267167. The cubic root of 1116691981 is about 1037.4753794128.

The spelling of 1116691981 in words is "one billion, one hundred sixteen million, six hundred ninety-one thousand, nine hundred eighty-one".