21285360 has 240 divisors, whose sum is σ = 79387776. Its totient is φ = 5087232.

The previous prime is 21285347. The next prime is 21285367. The reversal of 21285360 is 6358212.

21285360 is a `hidden beast` number, since 2 + 128 + 536 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21285367) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 452857 + ... + 452903.

Almost surely, 2^21285360 is an apocalyptic number.

21285360 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

21285360 is the 2664-th octagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21285360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39693888).

21285360 is an abundant number, since it is smaller than the sum of its proper divisors (58102416).

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

21285360 is a wasteful number, since it uses less digits than its factorization.

21285360 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120 (or 111 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 21285360 is about 4613.6059649693. The cubic root of 21285360 is about 277.1364608902.

The spelling of 21285360 in words is "twenty-one million, two hundred eighty-five thousand, three hundred sixty".