1111981 has 8 divisors (see below), whose sum is σ = 1249920. Its totient is φ = 981552.

The previous prime is 1111967. The next prime is 1111991. The reversal of 1111981 is 1891111.

It is the 431-st star number.

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

It is not a de Polignac number, because 1111981 - 2⁵ = 1111949 is a prime.

It is a super-2 number, since 2×1111981² = 2473003488722, 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 (1111921) 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 7 ways as a sum of consecutive naturals, for example, 1561 + ... + 2158.

It is an arithmetic number, because the mean of its divisors is an integer number (156240).

2^1111981 is an apocalyptic number.

It is an amenable number.

1111981 is a deficient number, since it is larger than the sum of its proper divisors (137939).

1111981 is a wasteful number, since it uses less digits than its factorization.

1111981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3755.

The product of its digits is 72, while the sum is 22.

The square root of 1111981 is about 1054.5050971901. The cubic root of 1111981 is about 103.6014392847.

The spelling of 1111981 in words is "one million, one hundred eleven thousand, nine hundred eighty-one".