21228680 has 32 divisors (see below), whose sum is σ = 52107840. Its totient is φ = 7719360.

The previous prime is 21228677. The next prime is 21228703. The reversal of 21228680 is 8682212.

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 7 ways as a sum of consecutive naturals, for example, 23684 + ... + 24563.

It is an arithmetic number, because the mean of its divisors is an integer number (1628370).

Almost surely, 2^21228680 is an apocalyptic number.

21228680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21228680 is an abundant number, since it is smaller than the sum of its proper divisors (30879160).

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

21228680 is a wasteful number, since it uses less digits than its factorization.

21228680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48269 (or 48265 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 29.

The square root of 21228680 is about 4607.4591696509. The cubic root of 21228680 is about 276.8902500658.

The spelling of 21228680 in words is "twenty-one million, two hundred twenty-eight thousand, six hundred eighty".