21166804 has 12 divisors (see below), whose sum is σ = 37564128. Its totient is φ = 10434200.

The previous prime is 21166799. The next prime is 21166807. The reversal of 21166804 is 40866112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21166807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36982 + ... + 37549.

It is an arithmetic number, because the mean of its divisors is an integer number (3130344).

Almost surely, 2^21166804 is an apocalyptic number.

It is an amenable number.

21166804 is a deficient number, since it is larger than the sum of its proper divisors (16397324).

21166804 is a wasteful number, since it uses less digits than its factorization.

21166804 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74606 (or 74604 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 21166804 is about 4600.7395057751. The cubic root of 21166804 is about 276.6209675975.

The spelling of 21166804 in words is "twenty-one million, one hundred sixty-six thousand, eight hundred four".