1991133 has 12 divisors (see below), whose sum is σ = 3001440. Its totient is φ = 1269576.

The previous prime is 1991131. The next prime is 1991137. The reversal of 1991133 is 3311991.

It is not a de Polignac number, because 1991133 - 2¹ = 1991131 is a prime.

It is a super-2 number, since 2×1991133² = 7929221247378, which contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 1991097 and 1991106.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1991131) 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 11 ways as a sum of consecutive naturals, for example, 4603 + ... + 5016.

It is an arithmetic number, because the mean of its divisors is an integer number (250120).

2^1991133 is an apocalyptic number.

It is an amenable number.

1991133 is a deficient number, since it is larger than the sum of its proper divisors (1010307).

1991133 is a wasteful number, since it uses less digits than its factorization.

1991133 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9648 (or 9645 counting only the distinct ones).

The product of its digits is 729, while the sum is 27.

The square root of 1991133 is about 1411.0751220258. The cubic root of 1991133 is about 125.8056338116.

The spelling of 1991133 in words is "one million, nine hundred ninety-one thousand, one hundred thirty-three".