21028360 has 16 divisors (see below), whose sum is σ = 47313900. Its totient is φ = 8411328.

The previous prime is 21028349. The next prime is 21028361. The reversal of 21028360 is 6382012.

It can be written as a sum of positive squares in 2 ways, for example, as 20738916 + 289444 = 4554^2 + 538^2 .

It is not an unprimeable number, because it can be changed into a prime (21028361) 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, 262815 + ... + 262894.

Almost surely, 2^21028360 is an apocalyptic number.

21028360 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21028360 is an abundant number, since it is smaller than the sum of its proper divisors (26285540).

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

21028360 is a wasteful number, since it uses less digits than its factorization.

21028360 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 525720 (or 525716 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 21028360 is about 4585.6689806396. The cubic root of 21028360 is about 276.0165571528.

The spelling of 21028360 in words is "twenty-one million, twenty-eight thousand, three hundred sixty".