21491200 has 120 divisors (see below), whose sum is σ = 56322288. Its totient is φ = 8110080.

The previous prime is 21491189. The next prime is 21491201. The reversal of 21491200 is 219412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21491201) 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 11 ways as a sum of consecutive naturals, for example, 294364 + ... + 294436.

Almost surely, 2^21491200 is an apocalyptic number.

21491200 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 21491200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28161144).

21491200 is an abundant number, since it is smaller than the sum of its proper divisors (34831088).

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

21491200 is an equidigital number, since it uses as much as digits as its factorization.

21491200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124 (or 103 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 21491200 is about 4635.8602222241. The cubic root of 21491200 is about 278.0269456138.

The spelling of 21491200 in words is "twenty-one million, four hundred ninety-one thousand, two hundred".