21066608 has 20 divisors (see below), whose sum is σ = 42134208. Its totient is φ = 10193280.

The previous prime is 21066607. The next prime is 21066613. The reversal of 21066608 is 80666012.

21066608 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21066601) 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 3 ways as a sum of consecutive naturals, for example, 20741 + ... + 21732.

Almost surely, 2^21066608 is an apocalyptic number.

It is an amenable number.

21066608 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21066608 is a wasteful number, since it uses less digits than its factorization.

21066608 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42512 (or 42506 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 21066608 is about 4589.8374698893. The cubic root of 21066608 is about 276.1838025151.

The spelling of 21066608 in words is "twenty-one million, sixty-six thousand, six hundred eight".