806991 has 4 divisors (see below), whose sum is σ = 1075992. Its totient is φ = 537992.

The previous prime is 806977. The next prime is 806999. The reversal of 806991 is 199608.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 806991 - 2¹⁰ = 805967 is a prime.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (806999) 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, 134496 + ... + 134501.

It is an arithmetic number, because the mean of its divisors is an integer number (268998).

2⁸⁰⁶⁹⁹¹ is an apocalyptic number.

806991 is a deficient number, since it is larger than the sum of its proper divisors (269001).

806991 is a wasteful number, since it uses less digits than its factorization.

806991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 269000.

The product of its (nonzero) digits is 3888, while the sum is 33.

The square root of 806991 is about 898.3267779600. The cubic root of 806991 is about 93.1014040183.

The spelling of 806991 in words is "eight hundred six thousand, nine hundred ninety-one".