21409912 has 8 divisors (see below), whose sum is σ = 40143600. Its totient is φ = 10704952.

The previous prime is 21409909. The next prime is 21409931. The reversal of 21409912 is 21990412.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is an unprimeable number.

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, 1338112 + ... + 1338127.

It is an arithmetic number, because the mean of its divisors is an integer number (5017950).

Almost surely, 2^21409912 is an apocalyptic number.

It is an amenable number.

21409912 is a deficient number, since it is larger than the sum of its proper divisors (18733688).

21409912 is a wasteful number, since it uses less digits than its factorization.

21409912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2676245 (or 2676241 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 28.

The square root of 21409912 is about 4627.0846112860. The cubic root of 21409912 is about 277.6759677147.

The spelling of 21409912 in words is "twenty-one million, four hundred nine thousand, nine hundred twelve".