21066844 has 6 divisors (see below), whose sum is σ = 36866984. Its totient is φ = 10533420.

The previous prime is 21066841. The next prime is 21066863. The reversal of 21066844 is 44866012.

It is a super-2 number, since 2×21066844² = 887623832240672, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21066841) 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 as a sum of consecutive naturals, namely, 2633352 + ... + 2633359.

Almost surely, 2^21066844 is an apocalyptic number.

It is an amenable number.

21066844 is a deficient number, since it is larger than the sum of its proper divisors (15800140).

21066844 is a wasteful number, since it uses less digits than its factorization.

21066844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5266715 (or 5266713 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 31.

The square root of 21066844 is about 4589.8631787887. The cubic root of 21066844 is about 276.1848338334.

The spelling of 21066844 in words is "twenty-one million, sixty-six thousand, eight hundred forty-four".