21804075 has 18 divisors (see below), whose sum is σ = 39053924. Its totient is φ = 11628720.

The previous prime is 21804073. The next prime is 21804089. The reversal of 21804075 is 57040812.

It is not a de Polignac number, because 21804075 - 2¹ = 21804073 is a prime.

It is a Duffinian number.

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

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 48229 + ... + 48678.

Almost surely, 2^21804075 is an apocalyptic number.

21804075 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21804075 is a deficient number, since it is larger than the sum of its proper divisors (17249849).

21804075 is a wasteful number, since it uses less digits than its factorization.

21804075 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96923 (or 96915 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 21804075 is about 4669.4833761349. The cubic root of 21804075 is about 279.3696491626.

Adding to 21804075 its reverse (57040812), we get a palindrome (78844887).

The spelling of 21804075 in words is "twenty-one million, eight hundred four thousand, seventy-five".