21416818 has 16 divisors (see below), whose sum is σ = 34027200. Its totient is φ = 10088496.

The previous prime is 21416807. The next prime is 21416827. The reversal of 21416818 is 81861412.

It is a self number, because there is not a number n which added to its sum of digits gives 21416818.

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 in 7 ways as a sum of consecutive naturals, for example, 393 + ... + 6556.

It is an arithmetic number, because the mean of its divisors is an integer number (2126700).

Almost surely, 2^21416818 is an apocalyptic number.

21416818 is a deficient number, since it is larger than the sum of its proper divisors (12610382).

21416818 is a wasteful number, since it uses less digits than its factorization.

21416818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7041.

The product of its digits is 3072, while the sum is 31.

The square root of 21416818 is about 4627.8308093533. The cubic root of 21416818 is about 277.7058203064.

The spelling of 21416818 in words is "twenty-one million, four hundred sixteen thousand, eight hundred eighteen".