268991 has 4 divisors (see below), whose sum is σ = 284832. Its totient is φ = 253152.

The previous prime is 268979. The next prime is 268993. The reversal of 268991 is 199862.

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 268991 - 2⁶ = 268927 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 268991.

It is not an unprimeable number, because it can be changed into a prime (268993) 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 3 ways as a sum of consecutive naturals, for example, 7895 + ... + 7928.

It is an arithmetic number, because the mean of its divisors is an integer number (71208).

2²⁶⁸⁹⁹¹ is an apocalyptic number.

268991 is a deficient number, since it is larger than the sum of its proper divisors (15841).

268991 is a wasteful number, since it uses less digits than its factorization.

268991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15840.

The product of its digits is 7776, while the sum is 35.

The square root of 268991 is about 518.6434227868. The cubic root of 268991 is about 64.5524281778.

The spelling of 268991 in words is "two hundred sixty-eight thousand, nine hundred ninety-one".