20668816 has 40 divisors (see below), whose sum is σ = 47250944. Its totient is φ = 8570880.

The previous prime is 20668811. The next prime is 20668819. The reversal of 20668816 is 61886602.

It is not an unprimeable number, because it can be changed into a prime (20668811) 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 7 ways as a sum of consecutive naturals, for example, 496 + ... + 6448.

Almost surely, 2^20668816 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20668816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23625472).

20668816 is an abundant number, since it is smaller than the sum of its proper divisors (26582128).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20668816 is a wasteful number, since it uses less digits than its factorization.

20668816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5999 (or 5993 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 37.

The square root of 20668816 is about 4546.2969546654. The cubic root of 20668816 is about 274.4343900889.

The spelling of 20668816 in words is "twenty million, six hundred sixty-eight thousand, eight hundred sixteen".