21021200 has 30 divisors (see below), whose sum is σ = 50504394. Its totient is φ = 8408320.

The previous prime is 21021181. The next prime is 21021229. The reversal of 21021200 is 212012.

It can be written as a sum of positive squares in 3 ways, for example, as 4892944 + 16128256 = 2212^2 + 4016^2 .

It is a Harshad number since it is a multiple of its sum of digits (8).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 25877 + ... + 26676.

Almost surely, 2^21021200 is an apocalyptic number.

21021200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21021200 is an abundant number, since it is smaller than the sum of its proper divisors (29483194).

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

21021200 is a wasteful number, since it uses less digits than its factorization.

21021200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52571 (or 52560 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 8.

The square root of 21021200 is about 4584.8882211020. Note that the first 3 decimals coincide. The cubic root of 21021200 is about 275.9852264024.

Adding to 21021200 its reverse (212012), we get a palindrome (21233212).

The spelling of 21021200 in words is "twenty-one million, twenty-one thousand, two hundred".