21101201321 has 2 divisors, whose sum is σ = 21101201322. Its totient is φ = 21101201320.

The previous prime is 21101201291. The next prime is 21101201353. The reversal of 21101201321 is 12310210112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18107470096 + 2993731225 = 134564^2 + 54715^2 .

It is a cyclic number.

It is not a de Polignac number, because 21101201321 - 2¹⁰ = 21101200297 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21101201296 and 21101201305.

It is not a weakly prime, because it can be changed into another prime (21101201221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550600660 + 10550600661.

It is an arithmetic number, because the mean of its divisors is an integer number (10550600661).

Almost surely, 2^21101201321 is an apocalyptic number.

It is an amenable number.

21101201321 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101201321 is an equidigital number, since it uses as much as digits as its factorization.

21101201321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 21101201321 its reverse (12310210112), we get a palindrome (33411411433).

The spelling of 21101201321 in words is "twenty-one billion, one hundred one million, two hundred one thousand, three hundred twenty-one".