20663021 has 8 divisors (see below), whose sum is σ = 20998560. Its totient is φ = 20330352.

The previous prime is 20663017. The next prime is 20663047. The reversal of 20663021 is 12036602.

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 20663021 - 2² = 20663017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20662984 and 20663002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20666021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17186 + ... + 18348.

It is an arithmetic number, because the mean of its divisors is an integer number (2624820).

Almost surely, 2^20663021 is an apocalyptic number.

It is an amenable number.

20663021 is a deficient number, since it is larger than the sum of its proper divisors (335539).

20663021 is a wasteful number, since it uses less digits than its factorization.

20663021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1435.

The product of its (nonzero) digits is 432, while the sum is 20.

The square root of 20663021 is about 4545.6595781031. The cubic root of 20663021 is about 274.4087395962.

Adding to 20663021 its reverse (12036602), we get a palindrome (32699623).

The spelling of 20663021 in words is "twenty million, six hundred sixty-three thousand, twenty-one".