1118581981 has 8 divisors (see below), whose sum is σ = 1232852544. Its totient is φ = 1006408320.

The previous prime is 1118581909. The next prime is 1118582011. The reversal of 1118581981 is 1891858111.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1118581981 - 2¹¹ = 1118579933 is a prime.

It is a super-2 number, since 2×1118581981² = 2502451296435768722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1118581381) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 523105 + ... + 525238.

It is an arithmetic number, because the mean of its divisors is an integer number (154106568).

Almost surely, 2^1118581981 is an apocalyptic number.

1118581981 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1118581981 is a deficient number, since it is larger than the sum of its proper divisors (114270563).

1118581981 is a wasteful number, since it uses less digits than its factorization.

1118581981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1048451.

The product of its digits is 23040, while the sum is 43.

The square root of 1118581981 is about 33445.2086404017. The cubic root of 1118581981 is about 1038.0603581733.

The spelling of 1118581981 in words is "one billion, one hundred eighteen million, five hundred eighty-one thousand, nine hundred eighty-one".