21251200 has 96 divisors (see below), whose sum is σ = 54544500. Its totient is φ = 8171520.

The previous prime is 21251179. The next prime is 21251201. The reversal of 21251200 is 215212.

It can be written as a sum of positive squares in 6 ways, for example, as 13366336 + 7884864 = 3656^2 + 2808^2 .

It is a super-2 number, since 2×21251200² = 903227002880000, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21251201) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 92686 + ... + 92914.

Almost surely, 2^21251200 is an apocalyptic number.

21251200 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 21251200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27272250).

21251200 is an abundant number, since it is smaller than the sum of its proper divisors (33293300).

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

21251200 is a wasteful number, since it uses less digits than its factorization.

21251200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 282 (or 265 counting only the distinct ones).

The product of its (nonzero) digits is 40, while the sum is 13.

The square root of 21251200 is about 4609.9023850837. The cubic root of 21251200 is about 276.9881265356.

Adding to 21251200 its reverse (215212), we get a palindrome (21466412).

The spelling of 21251200 in words is "twenty-one million, two hundred fifty-one thousand, two hundred".