21286760 has 64 divisors (see below), whose sum is σ = 52876800. Its totient is φ = 7648000.

The previous prime is 21286751. The next prime is 21286781. The reversal of 21286760 is 6768212.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 44201 + ... + 44679.

It is an arithmetic number, because the mean of its divisors is an integer number (826200).

Almost surely, 2^21286760 is an apocalyptic number.

21286760 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 21286760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26438400).

21286760 is an abundant number, since it is smaller than the sum of its proper divisors (31590040).

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

21286760 is a wasteful number, since it uses less digits than its factorization.

21286760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 602 (or 598 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 32.

The square root of 21286760 is about 4613.7576876121. The cubic root of 21286760 is about 277.1425367805.

It can be divided in two parts, 2128 and 6760, that added together give a palindrome (8888).

The spelling of 21286760 in words is "twenty-one million, two hundred eighty-six thousand, seven hundred sixty".