201220001221 has 4 divisors (see below), whose sum is σ = 202688760492. Its totient is φ = 199751241952.

The previous prime is 201220001209. The next prime is 201220001231. The reversal of 201220001221 is 122100022102.

It is a happy number.

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 118500489121 + 82719512100 = 344239^2 + 287610^2 .

It is a cyclic number.

It is not a de Polignac number, because 201220001221 - 2²⁵ = 201186446789 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 (201220001231) 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, 734379430 + ... + 734379703.

It is an arithmetic number, because the mean of its divisors is an integer number (50672190123).

Almost surely, 2^201220001221 is an apocalyptic number.

It is an amenable number.

201220001221 is a deficient number, since it is larger than the sum of its proper divisors (1468759271).

201220001221 is a wasteful number, since it uses less digits than its factorization.

201220001221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1468759270.

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

Adding to 201220001221 its reverse (122100022102), we get a palindrome (323320023323).

The spelling of 201220001221 in words is "two hundred one billion, two hundred twenty million, one thousand, two hundred twenty-one".