21405112 has 16 divisors (see below), whose sum is σ = 40195800. Its totient is φ = 10686240.

The previous prime is 21405067. The next prime is 21405113. The reversal of 21405112 is 21150412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21405113) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4939 + ... + 8197.

Almost surely, 2^21405112 is an apocalyptic number.

It is an amenable number.

21405112 is a deficient number, since it is larger than the sum of its proper divisors (18790688).

21405112 is a wasteful number, since it uses less digits than its factorization.

21405112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4086 (or 4082 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 21405112 is about 4626.5658970774. The cubic root of 21405112 is about 277.6552149552.

Adding to 21405112 its reverse (21150412), we get a palindrome (42555524).

The spelling of 21405112 in words is "twenty-one million, four hundred five thousand, one hundred twelve".