8187921 has 12 divisors (see below), whose sum is σ = 13516672. Its totient is φ = 4678776.

The previous prime is 8187919. The next prime is 8187929. The reversal of 8187921 is 1297818.

8187921 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 8187921 - 2¹ = 8187919 is a prime.

It is a Duffinian number.

8187921 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (8187929) 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 11 ways as a sum of consecutive naturals, for example, 64921 + ... + 65046.

Almost surely, 2^8187921 is an apocalyptic number.

It is an amenable number.

8187921 is a deficient number, since it is larger than the sum of its proper divisors (5328751).

8187921 is a wasteful number, since it uses less digits than its factorization.

8187921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129980 (or 129977 counting only the distinct ones).

The product of its digits is 8064, while the sum is 36.

The square root of 8187921 is about 2861.4543505008. The cubic root of 8187921 is about 201.5539039781.

The spelling of 8187921 in words is "eight million, one hundred eighty-seven thousand, nine hundred twenty-one".