21001222201 has 4 divisors (see below), whose sum is σ = 21017145600. Its totient is φ = 20985298804.

The previous prime is 21001222189. The next prime is 21001222219. The reversal of 21001222201 is 10222210012.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21001222201 - 2¹¹ = 21001220153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21001222301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7959721 + ... + 7962358.

It is an arithmetic number, because the mean of its divisors is an integer number (5254286400).

Almost surely, 2^21001222201 is an apocalyptic number.

It is an amenable number.

21001222201 is a deficient number, since it is larger than the sum of its proper divisors (15923399).

21001222201 is a wasteful number, since it uses less digits than its factorization.

21001222201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15923398.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21001222201 its reverse (10222210012), we get a palindrome (31223432213).

The spelling of 21001222201 in words is "twenty-one billion, one million, two hundred twenty-two thousand, two hundred one".