21807201 has 16 divisors (see below), whose sum is σ = 31981824. Its totient is φ = 13133184.

The previous prime is 21807187. The next prime is 21807211. The reversal of 21807201 is 10270812.

It is not a de Polignac number, because 21807201 - 2¹⁰ = 21806177 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21807211) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4116 + ... + 7781.

It is an arithmetic number, because the mean of its divisors is an integer number (1998864).

Almost surely, 2^21807201 is an apocalyptic number.

It is an amenable number.

21807201 is a deficient number, since it is larger than the sum of its proper divisors (10174623).

21807201 is a wasteful number, since it uses less digits than its factorization.

21807201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11960.

The product of its (nonzero) digits is 224, while the sum is 21.

The square root of 21807201 is about 4669.8180906755. The cubic root of 21807201 is about 279.3829993856.

The spelling of 21807201 in words is "twenty-one million, eight hundred seven thousand, two hundred one".