21545200 has 60 divisors (see below), whose sum is σ = 52670488. Its totient is φ = 8467200.

The previous prime is 21545191. The next prime is 21545201. The reversal of 21545200 is 254512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21545201) 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, 23959 + ... + 24841.

Almost surely, 2^21545200 is an apocalyptic number.

21545200 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 21545200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26335244).

21545200 is an abundant number, since it is smaller than the sum of its proper divisors (31125288).

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

21545200 is a wasteful number, since it uses less digits than its factorization.

21545200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 962 (or 951 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 19.

The square root of 21545200 is about 4641.6807300804. The cubic root of 21545200 is about 278.2596129076.

Adding to 21545200 its reverse (254512), we get a palindrome (21799712).

The spelling of 21545200 in words is "twenty-one million, five hundred forty-five thousand, two hundred".