It is a semiprime because it is the product of two primes.
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-20662511 is a prime.
It is a Duffinian number.
It is a congruent number.
Almost surely, 220662511 is an apocalyptic number.
20662511 is an equidigital number, since it uses as much as digits as its factorization.
20662511 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 92880.
The square root of 20662511 is about 4545.6034802873. The cubic root of 20662511 is about 274.4064819462.
The spelling of 20662511 in words is "twenty million, six hundred sixty-two thousand, five hundred eleven".