21440005 has 8 divisors (see below), whose sum is σ = 25754400. Its totient is φ = 17134416.

The previous prime is 21439997. The next prime is 21440017. The reversal of 21440005 is 50004412.

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

It is a cyclic number.

It is not a de Polignac number, because 21440005 - 2³ = 21439997 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5826 + ... + 8764.

It is an arithmetic number, because the mean of its divisors is an integer number (3219300).

Almost surely, 2^21440005 is an apocalyptic number.

It is an amenable number.

21440005 is a deficient number, since it is larger than the sum of its proper divisors (4314395).

21440005 is a wasteful number, since it uses less digits than its factorization.

21440005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4403.

The product of its (nonzero) digits is 160, while the sum is 16.

The square root of 21440005 is about 4630.3353010338. The cubic root of 21440005 is about 277.8060039169.

Adding to 21440005 its reverse (50004412), we get a palindrome (71444417).

The spelling of 21440005 in words is "twenty-one million, four hundred forty thousand, five".