1121991 has 12 divisors (see below), whose sum is σ = 1620648. Its totient is φ = 690144.

The previous prime is 1121987. The next prime is 1121993. The reversal of 1121991 is 1991211.

It is not a de Polignac number, because 1121991 - 2² = 1121987 is a prime.

It is an Ulam number.

1121991 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1121993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 600 + ... + 1613.

It is an arithmetic number, because the mean of its divisors is an integer number (135054).

2^1121991 is an apocalyptic number.

1121991 is a deficient number, since it is larger than the sum of its proper divisors (498657).

1121991 is a wasteful number, since it uses less digits than its factorization.

1121991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2242 (or 2229 counting only the distinct ones).

The product of its digits is 162, while the sum is 24.

The square root of 1121991 is about 1059.2407658318. The cubic root of 1121991 is about 103.9113828452.

It can be divided in two parts, 1121 and 991, that added together give a palindrome (2112).

The spelling of 1121991 in words is "one million, one hundred twenty-one thousand, nine hundred ninety-one".