21628208 has 50 divisors (see below), whose sum is σ = 48972684. Its totient is φ = 9252768.

The previous prime is 21628193. The next prime is 21628219. The reversal of 21628208 is 80282612.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 38135 + ... + 38697.

Almost surely, 2^21628208 is an apocalyptic number.

21628208 is a gapful number since it is divisible by the number (28) 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 21628208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24486342).

21628208 is an abundant number, since it is smaller than the sum of its proper divisors (27344476).

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

21628208 is an frugal number, since it uses more digits than its factorization.

21628208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 599 (or 572 counting only the distinct ones).

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

The square root of 21628208 is about 4650.6137229402. The cubic root of 21628208 is about 278.6165087058.

The spelling of 21628208 in words is "twenty-one million, six hundred twenty-eight thousand, two hundred eight".