21826004 has 24 divisors (see below), whose sum is σ = 39692520. Its totient is φ = 10492416.

The previous prime is 21825997. The next prime is 21826019. The reversal of 21826004 is 40062812.

It can be written as a sum of positive squares in 4 ways, for example, as 2729104 + 19096900 = 1652^2 + 4370^2 .

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 12344 + ... + 14000.

It is an arithmetic number, because the mean of its divisors is an integer number (1653855).

Almost surely, 2^21826004 is an apocalyptic number.

It is an amenable number.

21826004 is a deficient number, since it is larger than the sum of its proper divisors (17866516).

21826004 is a wasteful number, since it uses less digits than its factorization.

21826004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1787 (or 1785 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 21826004 is about 4671.8309044742. The cubic root of 21826004 is about 279.4632745420.

Adding to 21826004 its reverse (40062812), we get a palindrome (61888816).

The spelling of 21826004 in words is "twenty-one million, eight hundred twenty-six thousand, four".