8421666 has 16 divisors (see below), whose sum is σ = 18374688. Its totient is φ = 2552000.

The previous prime is 8421653. The next prime is 8421697. The reversal of 8421666 is 6661248.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 63735 + ... + 63866.

It is an arithmetic number, because the mean of its divisors is an integer number (1148418).

Almost surely, 2^8421666 is an apocalyptic number.

8421666 is an abundant number, since it is smaller than the sum of its proper divisors (9953022).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

8421666 is a wasteful number, since it uses less digits than its factorization.

8421666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127617.

The product of its digits is 13824, while the sum is 33.

The square root of 8421666 is about 2902.0106822684. The cubic root of 8421666 is about 203.4538930893.

The spelling of 8421666 in words is "eight million, four hundred twenty-one thousand, six hundred sixty-six".