21360001 has 4 divisors (see below), whose sum is σ = 23003092. Its totient is φ = 19716912.

The previous prime is 21359999. The next prime is 21360013. The reversal of 21360001 is 10006312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14070001 + 7290000 = 3751^2 + 2700^2 .

It is a cyclic number.

It is not a de Polignac number, because 21360001 - 2¹ = 21359999 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13), and also a Moran number because the ratio is a prime number: 1643077 = 21360001 / (2 + 1 + 3 + 6 + 0 + 0 + 0 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21360401) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 821526 + ... + 821551.

It is an arithmetic number, because the mean of its divisors is an integer number (5750773).

Almost surely, 2^21360001 is an apocalyptic number.

It is an amenable number.

21360001 is a deficient number, since it is larger than the sum of its proper divisors (1643091).

21360001 is a wasteful number, since it uses less digits than its factorization.

21360001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1643090.

The product of its (nonzero) digits is 36, while the sum is 13.

The square root of 21360001 is about 4621.6881115021. The cubic root of 21360001 is about 277.4600261659.

Adding to 21360001 its reverse (10006312), we get a palindrome (31366313).

The spelling of 21360001 in words is "twenty-one million, three hundred sixty thousand, one".