21405201 has 8 divisors (see below), whose sum is σ = 28607040. Its totient is φ = 14236752.

The previous prime is 21405187. The next prime is 21405247. The reversal of 21405201 is 10250412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21405201 - 2⁵ = 21405169 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21405401) by changing a digit.

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, 6810 + ... + 9443.

It is an arithmetic number, because the mean of its divisors is an integer number (3575880).

Almost surely, 2^21405201 is an apocalyptic number.

It is an amenable number.

21405201 is a deficient number, since it is larger than the sum of its proper divisors (7201839).

21405201 is a wasteful number, since it uses less digits than its factorization.

21405201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16695.

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 21405201 is about 4626.5755154326. The cubic root of 21405201 is about 277.6555997742.

Adding to 21405201 its reverse (10250412), we get a palindrome (31655613).

The spelling of 21405201 in words is "twenty-one million, four hundred five thousand, two hundred one".