21855300 has 72 divisors (see below), whose sum is σ = 63704256. Its totient is φ = 5784960.

The previous prime is 21855293. The next prime is 21855331. The reversal of 21855300 is 355812.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 78762 + ... + 79038.

Almost surely, 2^21855300 is an apocalyptic number.

21855300 is a gapful number since it is divisible by the number (20) 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 21855300, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31852128).

21855300 is an abundant number, since it is smaller than the sum of its proper divisors (41848956).

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

21855300 is a wasteful number, since it uses less digits than its factorization.

21855300 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 557 (or 550 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 24.

The square root of 21855300 is about 4674.9652405125. The cubic root of 21855300 is about 279.5882553637.

It can be divided in two parts, 21855 and 300, that added together give a triangular number (22155 = T₂₁₀).

The spelling of 21855300 in words is "twenty-one million, eight hundred fifty-five thousand, three hundred".