201221100001 has 4 divisors (see below), whose sum is σ = 201969134100. Its totient is φ = 200473065904.

The previous prime is 201221099993. The next prime is 201221100029. The reversal of 201221100001 is 100001122102.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 75638750625 + 125582349376 = 275025^2 + 354376^2 .

It is a cyclic number.

It is not a de Polignac number, because 201221100001 - 2³ = 201221099993 is a prime.

It is a super-2 number, since 2×201221100001² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (201221100401) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 374016646 + ... + 374017183.

It is an arithmetic number, because the mean of its divisors is an integer number (50492283525).

Almost surely, 2^201221100001 is an apocalyptic number.

It is an amenable number.

201221100001 is a deficient number, since it is larger than the sum of its proper divisors (748034099).

201221100001 is an equidigital number, since it uses as much as digits as its factorization.

201221100001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 748034098.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 201221100001 its reverse (100001122102), we get a palindrome (301222222103).

The spelling of 201221100001 in words is "two hundred one billion, two hundred twenty-one million, one hundred thousand, one".