21728600 has 24 divisors (see below), whose sum is σ = 50519460. Its totient is φ = 8691360.

The previous prime is 21728593. The next prime is 21728621. The reversal of 21728600 is 682712.

It is a self number, because there is not a number n which added to its sum of digits gives 21728600.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 54122 + ... + 54521.

Almost surely, 2^21728600 is an apocalyptic number.

21728600 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21728600 is an abundant number, since it is smaller than the sum of its proper divisors (28790860).

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

21728600 is a wasteful number, since it uses less digits than its factorization.

21728600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108659 (or 108650 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 21728600 is about 4661.3946410919. The cubic root of 21728600 is about 279.0469296664.

The spelling of 21728600 in words is "twenty-one million, seven hundred twenty-eight thousand, six hundred".