21447418 has 8 divisors (see below), whose sum is σ = 32212512. Its totient is φ = 10709916.

The previous prime is 21447407. The next prime is 21447427. The reversal of 21447418 is 81474412.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21447418.

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 3 ways as a sum of consecutive naturals, for example, 4830 + ... + 8137.

It is an arithmetic number, because the mean of its divisors is an integer number (4026564).

Almost surely, 2^21447418 is an apocalyptic number.

21447418 is a deficient number, since it is larger than the sum of its proper divisors (10765094).

21447418 is a wasteful number, since it uses less digits than its factorization.

21447418 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13796.

The product of its digits is 7168, while the sum is 31.

The square root of 21447418 is about 4631.1357138395. The cubic root of 21447418 is about 277.8380178803.

The spelling of 21447418 in words is "twenty-one million, four hundred forty-seven thousand, four hundred eighteen".