8491987 has 4 divisors (see below), whose sum is σ = 9705136. Its totient is φ = 7278840.

The previous prime is 8491969. The next prime is 8492039. The reversal of 8491987 is 7891948.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8491987 is a prime.

It is a super-2 number, since 2×8491987² = 144227686416338, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (8491487) 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, 606564 + ... + 606577.

It is an arithmetic number, because the mean of its divisors is an integer number (2426284).

Almost surely, 2^8491987 is an apocalyptic number.

8491987 is a deficient number, since it is larger than the sum of its proper divisors (1213149).

8491987 is a wasteful number, since it uses less digits than its factorization.

8491987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1213148.

The product of its digits is 145152, while the sum is 46.

The square root of 8491987 is about 2914.1014052363. The cubic root of 8491987 is about 204.0186049288.

The spelling of 8491987 in words is "eight million, four hundred ninety-one thousand, nine hundred eighty-seven".