16821166 has 4 divisors (see below), whose sum is σ = 25231752. Its totient is φ = 8410582.

The previous prime is 16821139. The next prime is 16821173. The reversal of 16821166 is 66112861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 66112861 = 827 ⋅79943.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 4205290 + ... + 4205293.

It is an arithmetic number, because the mean of its divisors is an integer number (6307938).

Almost surely, 2^16821166 is an apocalyptic number.

16821166 is a deficient number, since it is larger than the sum of its proper divisors (8410586).

16821166 is an equidigital number, since it uses as much as digits as its factorization.

16821166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8410585.

The product of its digits is 3456, while the sum is 31.

The square root of 16821166 is about 4101.3614812645. The cubic root of 16821166 is about 256.2233463453.

The spelling of 16821166 in words is "sixteen million, eight hundred twenty-one thousand, one hundred sixty-six".