21825408 has 64 divisors (see below), whose sum is σ = 63256320. Its totient is φ = 6612480.

The previous prime is 21825403. The next prime is 21825439. The reversal of 21825408 is 80452812.

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21825403) 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, 1641 + ... + 6807.

It is an arithmetic number, because the mean of its divisors is an integer number (988380).

Almost surely, 2^21825408 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 21825408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31628160).

21825408 is an abundant number, since it is smaller than the sum of its proper divisors (41430912).

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

21825408 is a wasteful number, since it uses less digits than its factorization.

21825408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5195 (or 5183 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 30.

The square root of 21825408 is about 4671.7671174835. The cubic root of 21825408 is about 279.4607307624.

The spelling of 21825408 in words is "twenty-one million, eight hundred twenty-five thousand, four hundred eight".