21265560 has 96 divisors (see below), whose sum is σ = 72774000. Its totient is φ = 5370624.

The previous prime is 21265553. The next prime is 21265577. The reversal of 21265560 is 6556212.

21265560 is a `hidden beast` number, since 2 + 1 + 2 + 655 + 6 + 0 = 666.

It is a super-2 number, since 2×21265560² = 904448084227200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5286 + ... + 8394.

Almost surely, 2^21265560 is an apocalyptic number.

21265560 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 21265560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36387000).

21265560 is an abundant number, since it is smaller than the sum of its proper divisors (51508440).

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

21265560 is a wasteful number, since it uses less digits than its factorization.

21265560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3145 (or 3138 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 21265560 is about 4611.4596387695. The cubic root of 21265560 is about 277.0505018983.

The spelling of 21265560 in words is "twenty-one million, two hundred sixty-five thousand, five hundred sixty".