21358944 has 96 divisors (see below), whose sum is σ = 63504000. Its totient is φ = 6982272.

The previous prime is 21358933. The next prime is 21358949. The reversal of 21358944 is 44985312.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21358899 and 21358908.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21358949) 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 15 ways as a sum of consecutive naturals, for example, 50767 + ... + 51185.

It is an arithmetic number, because the mean of its divisors is an integer number (661500).

Almost surely, 2^21358944 is an apocalyptic number.

21358944 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21358944, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31752000).

21358944 is an abundant number, since it is smaller than the sum of its proper divisors (42145056).

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

21358944 is a wasteful number, since it uses less digits than its factorization.

21358944 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 497 (or 483 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 21358944 is about 4621.5737579314. The cubic root of 21358944 is about 277.4554493857.

The spelling of 21358944 in words is "twenty-one million, three hundred fifty-eight thousand, nine hundred forty-four".