21715200 has 324 divisors, whose sum is σ = 86491860. Its totient is φ = 5160960.

The previous prime is 21715153. The next prime is 21715217. The reversal of 21715200 is 251712.

It can be written as a sum of positive squares in 6 ways, for example, as 2214144 + 19501056 = 1488^2 + 4416^2 .

It is a super-2 number, since 2×21715200² = 943099822080000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 748786 + ... + 748814.

Almost surely, 2^21715200 is an apocalyptic number.

21715200 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 21715200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43245930).

21715200 is an abundant number, since it is smaller than the sum of its proper divisors (64776660).

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

21715200 is a wasteful number, since it uses less digits than its factorization.

21715200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74 (or 52 counting only the distinct ones).

The product of its (nonzero) digits is 140, while the sum is 18.

The square root of 21715200 is about 4659.9570813474. The cubic root of 21715200 is about 278.9895552416.

Adding to 21715200 its reverse (251712), we get a palindrome (21966912).

The spelling of 21715200 in words is "twenty-one million, seven hundred fifteen thousand, two hundred".