21804076 has 12 divisors (see below), whose sum is σ = 43608208. Its totient is φ = 9344592.

The previous prime is 21804073. The next prime is 21804089. The reversal of 21804076 is 67040812.

21804076 is an admirable number.

It is a Harshad number since it is a multiple of its sum of digits (28), and also a Moran number because the ratio is a prime number: 778717 = 21804076 / (2 + 1 + 8 + 0 + 4 + 0 + 7 + 6).

It is not an unprimeable number, because it can be changed into a prime (21804073) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 389331 + ... + 389386.

Almost surely, 2^21804076 is an apocalyptic number.

It is an amenable number.

21804076 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21804076 is a wasteful number, since it uses less digits than its factorization.

21804076 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 778728 (or 778726 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 28.

The square root of 21804076 is about 4669.4834832131. The cubic root of 21804076 is about 279.3696534335.

Adding to 21804076 its reverse (67040812), we get a palindrome (88844888).

The spelling of 21804076 in words is "twenty-one million, eight hundred four thousand, seventy-six".