21438912 has 56 divisors (see below), whose sum is σ = 61886592. Its totient is φ = 6496000.

The previous prime is 21438881. The next prime is 21438913. The reversal of 21438912 is 21983412.

It is a self number, because there is not a number n which added to its sum of digits gives 21438912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21438913) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2964 + ... + 7187.

Almost surely, 2^21438912 is an apocalyptic number.

21438912 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21438912 is an abundant number, since it is smaller than the sum of its proper divisors (40447680).

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

21438912 is a wasteful number, since it uses less digits than its factorization.

21438912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10177 (or 10167 counting only the distinct ones).

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

The square root of 21438912 is about 4630.2172735197. The cubic root of 21438912 is about 277.8012830361.

The spelling of 21438912 in words is "twenty-one million, four hundred thirty-eight thousand, nine hundred twelve".