21536001 has 12 divisors (see below), whose sum is σ = 31239780. Its totient is φ = 14296320.

The previous prime is 21535993. The next prime is 21536033. The reversal of 21536001 is 10063512.

It can be written as a sum of positive squares in 2 ways, for example, as 10246401 + 11289600 = 3201^2 + 3360^2 .

It is not a de Polignac number, because 21536001 - 2³ = 21535993 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21536071) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2796 + ... + 7133.

It is an arithmetic number, because the mean of its divisors is an integer number (2603315).

Almost surely, 2^21536001 is an apocalyptic number.

It is an amenable number.

21536001 is a deficient number, since it is larger than the sum of its proper divisors (9703779).

21536001 is a wasteful number, since it uses less digits than its factorization.

21536001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10176 (or 10173 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 18.

The square root of 21536001 is about 4640.6897116700. The cubic root of 21536001 is about 278.2200050976.

Adding to 21536001 its reverse (10063512), we get a palindrome (31599513).

The spelling of 21536001 in words is "twenty-one million, five hundred thirty-six thousand, one".