21201222211 has 6 divisors (see below), whose sum is σ = 22957536660. Its totient is φ = 19570358808.

The previous prime is 21201222209. The next prime is 21201222253. The reversal of 21201222211 is 11222210212.

It is a happy number.

It is not a de Polignac number, because 21201222211 - 2¹ = 21201222209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21201222011) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 62725341 + ... + 62725678.

It is an arithmetic number, because the mean of its divisors is an integer number (3826256110).

Almost surely, 2^21201222211 is an apocalyptic number.

21201222211 is a deficient number, since it is larger than the sum of its proper divisors (1756314449).

21201222211 is a wasteful number, since it uses less digits than its factorization.

21201222211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125451045 (or 125451032 counting only the distinct ones).

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

Adding to 21201222211 its reverse (11222210212), we get a palindrome (32423432423).

The spelling of 21201222211 in words is "twenty-one billion, two hundred one million, two hundred twenty-two thousand, two hundred eleven".