21028960 has 24 divisors (see below), whose sum is σ = 49681296. Its totient is φ = 8411520.

The previous prime is 21028939. The next prime is 21028979. The reversal of 21028960 is 6982012.

It is a happy number.

It is a Smith number, since the sum of its digits (28) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 65556 + ... + 65875.

It is an arithmetic number, because the mean of its divisors is an integer number (2070054).

Almost surely, 2^21028960 is an apocalyptic number.

21028960 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21028960 is an abundant number, since it is smaller than the sum of its proper divisors (28652336).

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

21028960 is a wasteful number, since it uses less digits than its factorization.

21028960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131446 (or 131438 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 21028960 is about 4585.7344013800. The cubic root of 21028960 is about 276.0191823117.

The spelling of 21028960 in words is "twenty-one million, twenty-eight thousand, nine hundred sixty".