21168449 has 8 divisors (see below), whose sum is σ = 21648480. Its totient is φ = 20693376.

The previous prime is 21168439. The next prime is 21168461. The reversal of 21168449 is 94486112.

It is a happy number.

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 21168449 - 2²⁰ = 20119873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21168409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8177 + ... + 10449.

It is an arithmetic number, because the mean of its divisors is an integer number (2706060).

Almost surely, 2^21168449 is an apocalyptic number.

It is an amenable number.

21168449 is a deficient number, since it is larger than the sum of its proper divisors (480031).

21168449 is a wasteful number, since it uses less digits than its factorization.

21168449 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2479.

The product of its digits is 13824, while the sum is 35.

The square root of 21168449 is about 4600.9182779093. The cubic root of 21168449 is about 276.6281333731.

The spelling of 21168449 in words is "twenty-one million, one hundred sixty-eight thousand, four hundred forty-nine".