21641760 has 288 divisors, whose sum is σ = 89631360. Its totient is φ = 4644864.

The previous prime is 21641747. The next prime is 21641783. The reversal of 21641760 is 6714612.

It is a tau number, because it is divible by the number of its divisors (288).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 191464 + ... + 191576.

It is an arithmetic number, because the mean of its divisors is an integer number (311220).

Almost surely, 2^21641760 is an apocalyptic number.

21641760 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 21641760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44815680).

21641760 is an abundant number, since it is smaller than the sum of its proper divisors (67989600).

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

21641760 is a wasteful number, since it uses less digits than its factorization.

21641760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160 (or 149 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 21641760 is about 4652.0705067744. The cubic root of 21641760 is about 278.6746892476.

The spelling of 21641760 in words is "twenty-one million, six hundred forty-one thousand, seven hundred sixty".