21550560 has 192 divisors, whose sum is σ = 76204800. Its totient is φ = 5087232.

The previous prime is 21550547. The next prime is 21550561. The reversal of 21550560 is 6505512.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21550560.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21550561) 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, 154971 + ... + 155109.

It is an arithmetic number, because the mean of its divisors is an integer number (396900).

Almost surely, 2^21550560 is an apocalyptic number.

21550560 is a gapful number since it is divisible by the number (20) 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 21550560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38102400).

21550560 is an abundant number, since it is smaller than the sum of its proper divisors (54654240).

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

21550560 is a wasteful number, since it uses less digits than its factorization.

21550560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 193 (or 185 counting only the distinct ones).

The product of its (nonzero) digits is 1500, while the sum is 24.

The square root of 21550560 is about 4642.2580712408. The cubic root of 21550560 is about 278.2826860725.

The spelling of 21550560 in words is "twenty-one million, five hundred fifty thousand, five hundred sixty".