21600004 has 6 divisors (see below), whose sum is σ = 37800014. Its totient is φ = 10800000.

The previous prime is 21600001. The next prime is 21600011. The reversal of 21600004 is 40000612.

It can be written as a sum of positive squares in only one way, i.e., 20793600 + 806404 = 4560^2 + 898^2 .

It is not an unprimeable number, because it can be changed into a prime (21600001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2699997 + ... + 2700004.

Almost surely, 2^21600004 is an apocalyptic number.

It is an amenable number.

21600004 is a deficient number, since it is larger than the sum of its proper divisors (16200010).

21600004 is a wasteful number, since it uses less digits than its factorization.

21600004 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5400005 (or 5400003 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 21600004 is about 4647.5804457804. The cubic root of 21600004 is about 278.4953472078.

Adding to 21600004 its reverse (40000612), we get a palindrome (61600616).

The spelling of 21600004 in words is "twenty-one million, six hundred thousand, four".