201021221221 has 16 divisors (see below), whose sum is σ = 211226402160. Its totient is φ = 191056499200.

The previous prime is 201021221179. The next prime is 201021221239. The reversal of 201021221221 is 122122120102.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 13912202500 + 187109018721 = 117950^2 + 432561^2 .

It is a cyclic number.

It is not a de Polignac number, because 201021221221 - 2¹⁵ = 201021188453 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 201021221195 and 201021221204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201021221251) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 308361 + ... + 705073.

It is an arithmetic number, because the mean of its divisors is an integer number (13201650135).

Almost surely, 2^201021221221 is an apocalyptic number.

It is an amenable number.

201021221221 is a deficient number, since it is larger than the sum of its proper divisors (10205180939).

201021221221 is a wasteful number, since it uses less digits than its factorization.

201021221221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 397016.

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

Adding to 201021221221 its reverse (122122120102), we get a palindrome (323143341323).

It can be divided in two parts, 20102 and 1221221, that multiplied together give a palindrome (24548984542).

The spelling of 201021221221 in words is "two hundred one billion, twenty-one million, two hundred twenty-one thousand, two hundred twenty-one".