21186560 has 48 divisors (see below), whose sum is σ = 50859900. Its totient is φ = 8470528.

The previous prime is 21186553. The next prime is 21186563. The reversal of 21186560 is 6568112.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 19784704 + 1401856 = 4448^2 + 1184^2 .

It is not an unprimeable number, because it can be changed into a prime (21186563) 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, 9206 + ... + 11274.

Almost surely, 2^21186560 is an apocalyptic number.

21186560 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 21186560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25429950).

21186560 is an abundant number, since it is smaller than the sum of its proper divisors (29673340).

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

21186560 is an equidigital number, since it uses as much as digits as its factorization.

21186560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2096 (or 2076 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 21186560 is about 4602.8860511640. The cubic root of 21186560 is about 276.7070020707.

The spelling of 21186560 in words is "twenty-one million, one hundred eighty-six thousand, five hundred sixty".