21184380 has 288 divisors, whose sum is σ = 83026944. Its totient is φ = 4257792.

The previous prime is 21184379. The next prime is 21184391. The reversal of 21184380 is 8348112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 492639 + ... + 492681.

It is an arithmetic number, because the mean of its divisors is an integer number (288288).

Almost surely, 2^21184380 is an apocalyptic number.

21184380 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 21184380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41513472).

21184380 is an abundant number, since it is smaller than the sum of its proper divisors (61842564).

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

21184380 is a wasteful number, since it uses less digits than its factorization.

21184380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105 (or 100 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 21184380 is about 4602.6492371242. The cubic root of 21184380 is about 276.6975111174.

The spelling of 21184380 in words is "twenty-one million, one hundred eighty-four thousand, three hundred eighty".