891987 has 8 divisors (see below), whose sum is σ = 1205904. Its totient is φ = 586368.

The previous prime is 891983. The next prime is 891991. The reversal of 891987 is 789198.

It is an interprime number because it is at equal distance from previous prime (891983) and next prime (891991).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 891987 - 2² = 891983 is a prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 891987.

It is not an unprimeable number, because it can be changed into a prime (891983) 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 7 ways as a sum of consecutive naturals, for example, 1818 + ... + 2255.

It is an arithmetic number, because the mean of its divisors is an integer number (150738).

2⁸⁹¹⁹⁸⁷ is an apocalyptic number.

891987 is a deficient number, since it is larger than the sum of its proper divisors (313917).

891987 is a wasteful number, since it uses less digits than its factorization.

891987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4149.

The product of its digits is 36288, while the sum is 42.

The square root of 891987 is about 944.4506339666. The cubic root of 891987 is about 96.2615480606.

The spelling of 891987 in words is "eight hundred ninety-one thousand, nine hundred eighty-seven".