221201021221 has 4 divisors (see below), whose sum is σ = 223391130444. Its totient is φ = 219010912000.

The previous prime is 221201021213. The next prime is 221201021303. The reversal of 221201021221 is 122120102122.

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 200533796100 + 20667225121 = 447810^2 + 143761^2 .

It is a cyclic number.

It is not a de Polignac number, because 221201021221 - 2³ = 221201021213 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221201021195 and 221201021204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221201022221) 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, 1095054460 + ... + 1095054661.

It is an arithmetic number, because the mean of its divisors is an integer number (55847782611).

Almost surely, 2^221201021221 is an apocalyptic number.

It is an amenable number.

221201021221 is a deficient number, since it is larger than the sum of its proper divisors (2190109223).

221201021221 is a wasteful number, since it uses less digits than its factorization.

221201021221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2190109222.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 221201021221 its reverse (122120102122), we get a palindrome (343321123343).

The spelling of 221201021221 in words is "two hundred twenty-one billion, two hundred one million, twenty-one thousand, two hundred twenty-one".