21489760 has 48 divisors (see below), whose sum is σ = 53449200. Its totient is φ = 8142336.

The previous prime is 21489739. The next prime is 21489761. The reversal of 21489760 is 6798412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21489761) 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 7 ways as a sum of consecutive naturals, for example, 495 + ... + 6574.

It is an arithmetic number, because the mean of its divisors is an integer number (1113525).

Almost surely, 2^21489760 is an apocalyptic number.

21489760 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 21489760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26724600).

21489760 is an abundant number, since it is smaller than the sum of its proper divisors (31959440).

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

21489760 is a wasteful number, since it uses less digits than its factorization.

21489760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7103 (or 7095 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 37.

The square root of 21489760 is about 4635.7049086412. The cubic root of 21489760 is about 278.0207358202.

The spelling of 21489760 in words is "twenty-one million, four hundred eighty-nine thousand, seven hundred sixty".