21380800 has 168 divisors, whose sum is σ = 63495936. Its totient is φ = 6927360.

The previous prime is 21380789. The next prime is 21380809. The reversal of 21380800 is 808312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21380809) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 257559 + ... + 257641.

It is an arithmetic number, because the mean of its divisors is an integer number (377952).

Almost surely, 2^21380800 is an apocalyptic number.

21380800 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 21380800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31747968).

21380800 is an abundant number, since it is smaller than the sum of its proper divisors (42115136).

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

21380800 is a wasteful number, since it uses less digits than its factorization.

21380800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135 (or 120 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 21380800 is about 4623.9377158435. The cubic root of 21380800 is about 277.5500545479.

The spelling of 21380800 in words is "twenty-one million, three hundred eighty thousand, eight hundred".