21201001321 has 4 divisors (see below), whose sum is σ = 21201746500. Its totient is φ = 21200256144.

The previous prime is 21201001307. The next prime is 21201001379. The reversal of 21201001321 is 12310010212.

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 19999616400 + 1201384921 = 141420^2 + 34661^2 .

It is a cyclic number.

It is not a de Polignac number, because 21201001321 - 2⁷ = 21201001193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21201001621) 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, 328146 + ... + 387403.

It is an arithmetic number, because the mean of its divisors is an integer number (5300436625).

Almost surely, 2^21201001321 is an apocalyptic number.

It is an amenable number.

21201001321 is a deficient number, since it is larger than the sum of its proper divisors (745179).

21201001321 is an equidigital number, since it uses as much as digits as its factorization.

21201001321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 745178.

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 21201001321 its reverse (12310010212), we get a palindrome (33511011533).

The spelling of 21201001321 in words is "twenty-one billion, two hundred one million, one thousand, three hundred twenty-one".