21384912 has 80 divisors (see below), whose sum is σ = 59460480. Its totient is φ = 6598656.

The previous prime is 21384907. The next prime is 21384931. The reversal of 21384912 is 21948312.

It is a super-2 number, since 2×21384912² = 914628922495488, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21384912.

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 in 15 ways as a sum of consecutive naturals, for example, 59389 + ... + 59747.

It is an arithmetic number, because the mean of its divisors is an integer number (743256).

Almost surely, 2^21384912 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 21384912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29730240).

21384912 is an abundant number, since it is smaller than the sum of its proper divisors (38075568).

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

21384912 is a wasteful number, since it uses less digits than its factorization.

21384912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 460 (or 454 counting only the distinct ones).

The product of its digits is 3456, while the sum is 30.

The square root of 21384912 is about 4624.3823371343. The cubic root of 21384912 is about 277.5678464089.

The spelling of 21384912 in words is "twenty-one million, three hundred eighty-four thousand, nine hundred twelve".