21040200 has 72 divisors (see below), whose sum is σ = 70666050. Its totient is φ = 5610240.

The previous prime is 21040199. The next prime is 21040213. The reversal of 21040200 is 204012.

It can be written as a sum of positive squares in 3 ways, for example, as 20304036 + 736164 = 4506^2 + 858^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (9).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 4045 + ... + 7644.

Almost surely, 2^21040200 is an apocalyptic number.

21040200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21040200 is an abundant number, since it is smaller than the sum of its proper divisors (49625850).

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

21040200 is a wasteful number, since it uses less digits than its factorization.

21040200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11711 (or 11699 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 9.

The square root of 21040200 is about 4586.9597774561. The cubic root of 21040200 is about 276.0683510615.

Adding to 21040200 its reverse (204012), we get a palindrome (21244212).

The spelling of 21040200 in words is "twenty-one million, forty thousand, two hundred".