201021100101221 has 4 divisors (see below), whose sum is σ = 201040938372492. Its totient is φ = 201001261829952.

The previous prime is 201021100101067. The next prime is 201021100101251. The reversal of 201021100101221 is 122101001120102.

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 61117387053121 + 139903713048100 = 7817761^2 + 11828090^2 .

It is a cyclic number.

It is not a de Polignac number, because 201021100101221 - 2¹⁴ = 201021100084837 is a prime.

It is a super-2 number, since 2×201021100101221² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 201021100101196 and 201021100101205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201021100101251) 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, 9919120436 + ... + 9919140701.

It is an arithmetic number, because the mean of its divisors is an integer number (50260234593123).

Almost surely, 2^{201021100101221} is an apocalyptic number.

It is an amenable number.

201021100101221 is a deficient number, since it is larger than the sum of its proper divisors (19838271271).

201021100101221 is a wasteful number, since it uses less digits than its factorization.

201021100101221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19838271270.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 201021100101221 its reverse (122101001120102), we get a palindrome (323122101221323).

The spelling of 201021100101221 in words is "two hundred one trillion, twenty-one billion, one hundred million, one hundred one thousand, two hundred twenty-one".