21804552 has 320 divisors, whose sum is σ = 83635200. Its totient is φ = 5132160.

The previous prime is 21804539. The next prime is 21804623. The reversal of 21804552 is 25540812.

It is a happy number.

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

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 948013 + ... + 948035.

It is an arithmetic number, because the mean of its divisors is an integer number (261360).

Almost surely, 2^21804552 is an apocalyptic number.

21804552 is a gapful number since it is divisible by the number (22) 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 21804552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41817600).

21804552 is an abundant number, since it is smaller than the sum of its proper divisors (61830648).

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

21804552 is a wasteful number, since it uses less digits than its factorization.

21804552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78 (or 65 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 27.

The square root of 21804552 is about 4669.5344521697. The cubic root of 21804552 is about 279.3716863712.

The spelling of 21804552 in words is "twenty-one million, eight hundred four thousand, five hundred fifty-two".