21041800 has 48 divisors (see below), whose sum is σ = 52691940. Its totient is φ = 7768320.

The previous prime is 21041771. The next prime is 21041807. The reversal of 21041800 is 814012.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 3452164 + 17589636 = 1858^2 + 4194^2 .

It is not an unprimeable number, because it can be changed into a prime (21041807) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 1447 + ... + 6646.

Almost surely, 2^21041800 is an apocalyptic number.

21041800 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21041800 is an abundant number, since it is smaller than the sum of its proper divisors (31650140).

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

21041800 is a wasteful number, since it uses less digits than its factorization.

21041800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8122 (or 8113 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

The square root of 21041800 is about 4587.1341815997. The cubic root of 21041800 is about 276.0753487479.

Adding to 21041800 its reverse (814012), we get a palindrome (21855812).

The spelling of 21041800 in words is "twenty-one million, forty-one thousand, eight hundred".