21440171 has 8 divisors (see below), whose sum is σ = 22180704. Its totient is φ = 20710080.

The previous prime is 21440149. The next prime is 21440183. The reversal of 21440171 is 17104412.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21440171 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21448171) 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 7 ways as a sum of consecutive naturals, for example, 1685 + ... + 6761.

It is an arithmetic number, because the mean of its divisors is an integer number (2772588).

Almost surely, 2^21440171 is an apocalyptic number.

21440171 is a deficient number, since it is larger than the sum of its proper divisors (740533).

21440171 is a wasteful number, since it uses less digits than its factorization.

21440171 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5221.

The product of its (nonzero) digits is 224, while the sum is 20.

The square root of 21440171 is about 4630.3532262669. The cubic root of 21440171 is about 277.8067208893.

Adding to 21440171 its reverse (17104412), we get a palindrome (38544583).

The spelling of 21440171 in words is "twenty-one million, four hundred forty thousand, one hundred seventy-one".