21202201001221 has 8 divisors (see below), whose sum is σ = 21314727185400. Its totient is φ = 21089724320448.

The previous prime is 21202201001161. The next prime is 21202201001269. The reversal of 21202201001221 is 12210010220212.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 134238700996 + 21067962300225 = 366386^2 + 4589985^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21202201001221 - 2¹⁵ = 21202200968453 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21202201001195 and 21202201001204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21202201001921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11516826 + ... + 13230331.

It is an arithmetic number, because the mean of its divisors is an integer number (2664340898175).

Almost surely, 2^{21202201001221} is an apocalyptic number.

It is an amenable number.

21202201001221 is a deficient number, since it is larger than the sum of its proper divisors (112526184179).

21202201001221 is a wasteful number, since it uses less digits than its factorization.

21202201001221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24751703.

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

Adding to 21202201001221 its reverse (12210010220212), we get a palindrome (33412211221433).

The spelling of 21202201001221 in words is "twenty-one trillion, two hundred two billion, two hundred one million, one thousand, two hundred twenty-one".