21222201 has 64 divisors (see below), whose sum is σ = 39223296. Its totient is φ = 9849600.

The previous prime is 21222181. The next prime is 21222211. The reversal of 21222201 is 10222212.

It is not a de Polignac number, because 21222201 - 2¹¹ = 21220153 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21222211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 111016 + ... + 111206.

It is an arithmetic number, because the mean of its divisors is an integer number (612864).

Almost surely, 2^21222201 is an apocalyptic number.

21222201 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21222201 is a deficient number, since it is larger than the sum of its proper divisors (18001095).

21222201 is a wasteful number, since it uses less digits than its factorization.

21222201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 262.

The product of its (nonzero) digits is 32, while the sum is 12.

The square root of 21222201 is about 4606.7560169820. The cubic root of 21222201 is about 276.8620782016.

Adding to 21222201 its reverse (10222212), we get a palindrome (31444413).

It can be divided in two parts, 21 and 222201, that added together give a palindrome (222222).

The spelling of 21222201 in words is "twenty-one million, two hundred twenty-two thousand, two hundred one".