21442560 has 104 divisors (see below), whose sum is σ = 68804400. Its totient is φ = 5701632.

The previous prime is 21442543. The next prime is 21442591. The reversal of 21442560 is 6524412.

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 21442560.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 61266 + ... + 61614.

Almost surely, 2^21442560 is an apocalyptic number.

21442560 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 21442560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34402200).

21442560 is an abundant number, since it is smaller than the sum of its proper divisors (47361840).

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

21442560 is an equidigital number, since it uses as much as digits as its factorization.

21442560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 381 (or 359 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 24.

The square root of 21442560 is about 4630.6111907609. The cubic root of 21442560 is about 277.8170388358.

Adding to 21442560 its reverse (6524412), we get a palindrome (27966972).

The spelling of 21442560 in words is "twenty-one million, four hundred forty-two thousand, five hundred sixty".