1066991 has 4 divisors (see below), whose sum is σ = 1071312. Its totient is φ = 1062672.

The previous prime is 1066987. The next prime is 1066999. The reversal of 1066991 is 1996601.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1996601 = 443 ⋅4507.

It is a cyclic number.

It is not a de Polignac number, because 1066991 - 2² = 1066987 is a prime.

It is a super-2 number, since 2×1066991² = 2276939588162, 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 (1066999) 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, 1766 + ... + 2291.

It is an arithmetic number, because the mean of its divisors is an integer number (267828).

2^1066991 is an apocalyptic number.

1066991 is a deficient number, since it is larger than the sum of its proper divisors (4321).

1066991 is an equidigital number, since it uses as much as digits as its factorization.

1066991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4320.

The product of its (nonzero) digits is 2916, while the sum is 32.

The square root of 1066991 is about 1032.9525642545. The cubic root of 1066991 is about 102.1849457569.

The spelling of 1066991 in words is "one million, sixty-six thousand, nine hundred ninety-one".