21708760 has 16 divisors (see below), whose sum is σ = 48844800. Its totient is φ = 8683488.

The previous prime is 21708749. The next prime is 21708761. The reversal of 21708760 is 6780712.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21708761) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 271320 + ... + 271399.

It is an arithmetic number, because the mean of its divisors is an integer number (3052800).

Almost surely, 2^21708760 is an apocalyptic number.

21708760 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21708760 is an abundant number, since it is smaller than the sum of its proper divisors (27136040).

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

21708760 is a wasteful number, since it uses less digits than its factorization.

21708760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 542730 (or 542726 counting only the distinct ones).

The product of its (nonzero) digits is 4704, while the sum is 31.

The square root of 21708760 is about 4659.2660366199. The cubic root of 21708760 is about 278.9619728665.

The spelling of 21708760 in words is "twenty-one million, seven hundred eight thousand, seven hundred sixty".