21200000 has 96 divisors (see below), whose sum is σ = 53785620. Its totient is φ = 8320000.

The previous prime is 21199999. The next prime is 21200021. The reversal of 21200000 is 212.

It can be written as a sum of positive squares in 6 ways, for example, as 1201216 + 19998784 = 1096^2 + 4472^2 .

It is a Harshad number since it is a multiple of its sum of digits (5).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 399974 + ... + 400026.

Almost surely, 2^21200000 is an apocalyptic number.

21200000 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 21200000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26892810).

21200000 is an abundant number, since it is smaller than the sum of its proper divisors (32585620).

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

21200000 is an frugal number, since it uses more digits than its factorization.

21200000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92 (or 60 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 5.

The square root of 21200000 is about 4604.3457732885. The cubic root of 21200000 is about 276.7655007289.

Adding to 21200000 its reverse (212), we get a palindrome (21200212).

21200000 divided by its reverse (212) gives a 5-th power (100000 = 10⁵).

The spelling of 21200000 in words is "twenty-one million, two hundred thousand".