21568449 has 16 divisors (see below), whose sum is σ = 33194880. Its totient is φ = 12201600.

The previous prime is 21568433. The next prime is 21568471. The reversal of 21568449 is 94486512.

It is not a de Polignac number, because 21568449 - 2⁴ = 21568433 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21568409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2964 + ... + 7205.

It is an arithmetic number, because the mean of its divisors is an integer number (2074680).

Almost surely, 2^21568449 is an apocalyptic number.

It is an amenable number.

21568449 is a deficient number, since it is larger than the sum of its proper divisors (11626431).

21568449 is a wasteful number, since it uses less digits than its factorization.

21568449 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10280.

The product of its digits is 69120, while the sum is 39.

The square root of 21568449 is about 4644.1844278624. The cubic root of 21568449 is about 278.3596650799.

The spelling of 21568449 in words is "twenty-one million, five hundred sixty-eight thousand, four hundred forty-nine".