20663449 has 4 divisors (see below), whose sum is σ = 21878964. Its totient is φ = 19447936.

The previous prime is 20663437. The next prime is 20663471. The reversal of 20663449 is 94436602.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13454224 + 7209225 = 3668^2 + 2685^2 .

It is a cyclic number.

It is not a de Polignac number, because 20663449 - 2⁵ = 20663417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20643449) 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 3 ways as a sum of consecutive naturals, for example, 607732 + ... + 607765.

It is an arithmetic number, because the mean of its divisors is an integer number (5469741).

Almost surely, 2^20663449 is an apocalyptic number.

It is an amenable number.

20663449 is a deficient number, since it is larger than the sum of its proper divisors (1215515).

20663449 is a wasteful number, since it uses less digits than its factorization.

20663449 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1215514.

The product of its (nonzero) digits is 31104, while the sum is 34.

The square root of 20663449 is about 4545.7066557357. The cubic root of 20663449 is about 274.4106342228.

It can be divided in two parts, 20663 and 449, that added together give a palindrome (21112).

The spelling of 20663449 in words is "twenty million, six hundred sixty-three thousand, four hundred forty-nine".