21560660 has 48 divisors (see below), whose sum is σ = 51553152. Its totient is φ = 7497600.

The previous prime is 21560647. The next prime is 21560689. The reversal of 21560660 is 6606512.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2930 + ... + 7190.

It is an arithmetic number, because the mean of its divisors is an integer number (1074024).

Almost surely, 2^21560660 is an apocalyptic number.

21560660 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 21560660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25776576).

21560660 is an abundant number, since it is smaller than the sum of its proper divisors (29992492).

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

21560660 is a wasteful number, since it uses less digits than its factorization.

21560660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4304 (or 4302 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 21560660 is about 4643.3457764849. The cubic root of 21560660 is about 278.3261530970.

The spelling of 21560660 in words is "twenty-one million, five hundred sixty thousand, six hundred sixty".