868991 has 4 divisors (see below), whose sum is σ = 875472. Its totient is φ = 862512.

The previous prime is 868957. The next prime is 868993. The reversal of 868991 is 199868.

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 868991 - 2¹⁸ = 606847 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (868993) 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, 3035 + ... + 3308.

It is an arithmetic number, because the mean of its divisors is an integer number (218868).

2⁸⁶⁸⁹⁹¹ is an apocalyptic number.

868991 is a deficient number, since it is larger than the sum of its proper divisors (6481).

868991 is a wasteful number, since it uses less digits than its factorization.

868991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6480.

The product of its digits is 31104, while the sum is 41.

The square root of 868991 is about 932.1968676197. The cubic root of 868991 is about 95.4271073752.

The spelling of 868991 in words is "eight hundred sixty-eight thousand, nine hundred ninety-one".