21021212221201 has 4 divisors (see below), whose sum is σ = 21035881596132. Its totient is φ = 21006542846272.

The previous prime is 21021212221169. The next prime is 21021212221213. The reversal of 21021212221201 is 10212221212012.

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 19053434520576 + 1967777700625 = 4365024^2 + 1402775^2 .

It is a cyclic number.

It is not a de Polignac number, because 21021212221201 - 2⁵ = 21021212221169 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21021212221501) 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, 7334685316 + ... + 7334688181.

It is an arithmetic number, because the mean of its divisors is an integer number (5258970399033).

Almost surely, 2^{21021212221201} is an apocalyptic number.

It is an amenable number.

21021212221201 is a deficient number, since it is larger than the sum of its proper divisors (14669374931).

21021212221201 is a wasteful number, since it uses less digits than its factorization.

21021212221201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14669374930.

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 21021212221201 its reverse (10212221212012), we get a palindrome (31233433433213).

The spelling of 21021212221201 in words is "twenty-one trillion, twenty-one billion, two hundred twelve million, two hundred twenty-one thousand, two hundred one".