21184172 has 6 divisors (see below), whose sum is σ = 37072308. Its totient is φ = 10592084.

The previous prime is 21184151. The next prime is 21184187. The reversal of 21184172 is 27148112.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 2648018 + ... + 2648025.

It is an arithmetic number, because the mean of its divisors is an integer number (6178718).

Almost surely, 2^21184172 is an apocalyptic number.

It is an amenable number.

21184172 is a deficient number, since it is larger than the sum of its proper divisors (15888136).

21184172 is a wasteful number, since it uses less digits than its factorization.

21184172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5296047 (or 5296045 counting only the distinct ones).

The product of its digits is 896, while the sum is 26.

The square root of 21184172 is about 4602.6266413864. The cubic root of 21184172 is about 276.6966055245.

The spelling of 21184172 in words is "twenty-one million, one hundred eighty-four thousand, one hundred seventy-two".