21366560 has 24 divisors (see below), whose sum is σ = 50478876. Its totient is φ = 8546560.

The previous prime is 21366557. The next prime is 21366581. The reversal of 21366560 is 6566312.

It can be written as a sum of positive squares in 2 ways, for example, as 21196816 + 169744 = 4604^2 + 412^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66611 + ... + 66930.

Almost surely, 2^21366560 is an apocalyptic number.

21366560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21366560 is an abundant number, since it is smaller than the sum of its proper divisors (29112316).

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

21366560 is a wasteful number, since it uses less digits than its factorization.

21366560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133556 (or 133548 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 29.

The square root of 21366560 is about 4622.3976462438. The cubic root of 21366560 is about 277.4884230757.

The spelling of 21366560 in words is "twenty-one million, three hundred sixty-six thousand, five hundred sixty".