21211222201 has 16 divisors (see below), whose sum is σ = 24426048528. Its totient is φ = 18245376000.

The previous prime is 21211222189. The next prime is 21211222217. The reversal of 21211222201 is 10222211212.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 460531600 + 20750690601 = 21460^2 + 144051^2 .

It is a cyclic number.

It is not a de Polignac number, because 21211222201 - 2⁵ = 21211222169 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21211222231) 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, 452820 + ... + 497461.

It is an arithmetic number, because the mean of its divisors is an integer number (1526628033).

Almost surely, 2^21211222201 is an apocalyptic number.

It is an amenable number.

21211222201 is a deficient number, since it is larger than the sum of its proper divisors (3214826327).

21211222201 is a wasteful number, since it uses less digits than its factorization.

21211222201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 950412.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21211222201 its reverse (10222211212), we get a palindrome (31433433413).

The spelling of 21211222201 in words is "twenty-one billion, two hundred eleven million, two hundred twenty-two thousand, two hundred one".