21010103231221 has 4 divisors (see below), whose sum is σ = 22626265018252. Its totient is φ = 19393941444192.

The previous prime is 21010103231219. The next prime is 21010103231237. The reversal of 21010103231221 is 12213230101012.

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 8096932851121 + 12913170380100 = 2845511^2 + 3593490^2 .

It is a cyclic number.

It is not a de Polignac number, because 21010103231221 - 2¹ = 21010103231219 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 (21010103231291) 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, 808080893496 + ... + 808080893521.

It is an arithmetic number, because the mean of its divisors is an integer number (5656566254563).

Almost surely, 2^{21010103231221} is an apocalyptic number.

It is an amenable number.

21010103231221 is a deficient number, since it is larger than the sum of its proper divisors (1616161787031).

21010103231221 is a wasteful number, since it uses less digits than its factorization.

21010103231221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1616161787030.

The product of its (nonzero) digits is 144, while the sum is 19.

Adding to 21010103231221 its reverse (12213230101012), we get a palindrome (33223333332233).

The spelling of 21010103231221 in words is "twenty-one trillion, ten billion, one hundred three million, two hundred thirty-one thousand, two hundred twenty-one".