21381200 has 30 divisors (see below), whose sum is σ = 51369294. Its totient is φ = 8552320.

The previous prime is 21381181. The next prime is 21381203. The reversal of 21381200 is 218312.

It can be written as a sum of positive squares in 3 ways, for example, as 1915456 + 19465744 = 1384^2 + 4412^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21381203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 26327 + ... + 27126.

Almost surely, 2^21381200 is an apocalyptic number.

21381200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21381200 is an abundant number, since it is smaller than the sum of its proper divisors (29988094).

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

21381200 is a wasteful number, since it uses less digits than its factorization.

21381200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53471 (or 53460 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 21381200 is about 4623.9809688190. The cubic root of 21381200 is about 277.5517853738.

Adding to 21381200 its reverse (218312), we get a palindrome (21599512).

The spelling of 21381200 in words is "twenty-one million, three hundred eighty-one thousand, two hundred".