201221210101 has 4 divisors (see below), whose sum is σ = 201232803232. Its totient is φ = 201209616972.

The previous prime is 201221210033. The next prime is 201221210117. The reversal of 201221210101 is 101012122102.

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 a de Polignac number, because none of the positive numbers 2^k-201221210101 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201221210131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5770491 + ... + 5805256.

It is an arithmetic number, because the mean of its divisors is an integer number (50308200808).

Almost surely, 2^201221210101 is an apocalyptic number.

It is an amenable number.

201221210101 is a deficient number, since it is larger than the sum of its proper divisors (11593131).

201221210101 is a wasteful number, since it uses less digits than its factorization.

201221210101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11593130.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 201221210101 its reverse (101012122102), we get a palindrome (302233332203).

The spelling of 201221210101 in words is "two hundred one billion, two hundred twenty-one million, two hundred ten thousand, one hundred one".