21440916 has 96 divisors (see below), whose sum is σ = 64512000. Its totient is φ = 6031584.

The previous prime is 21440891. The next prime is 21440917. The reversal of 21440916 is 61904412.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 21440916.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21440917) 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 in 31 ways as a sum of consecutive naturals, for example, 59545 + ... + 59903.

It is an arithmetic number, because the mean of its divisors is an integer number (672000).

Almost surely, 2^21440916 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 21440916, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32256000).

21440916 is an abundant number, since it is smaller than the sum of its proper divisors (43071084).

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

21440916 is a wasteful number, since it uses less digits than its factorization.

21440916 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 458 (or 450 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 21440916 is about 4630.4336729944. The cubic root of 21440916 is about 277.8099385815.

The spelling of 21440916 in words is "twenty-one million, four hundred forty thousand, nine hundred sixteen".