21121303321 has 4 divisors (see below), whose sum is σ = 21519818532. Its totient is φ = 20722788112.

The previous prime is 21121303309. The next prime is 21121303349. The reversal of 21121303321 is 12330312112.

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 7879047696 + 13242255625 = 88764^2 + 115075^2 .

It is a cyclic number.

It is not a de Polignac number, because 21121303321 - 2¹⁹ = 21120779033 is a prime.

It is a super-2 number, since 2×21121303321² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21121303391) 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, 199257526 + ... + 199257631.

It is an arithmetic number, because the mean of its divisors is an integer number (5379954633).

Almost surely, 2^21121303321 is an apocalyptic number.

It is an amenable number.

21121303321 is a deficient number, since it is larger than the sum of its proper divisors (398515211).

21121303321 is an equidigital number, since it uses as much as digits as its factorization.

21121303321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 398515210.

The product of its (nonzero) digits is 216, while the sum is 19.

Adding to 21121303321 its reverse (12330312112), we get a palindrome (33451615433).

The spelling of 21121303321 in words is "twenty-one billion, one hundred twenty-one million, three hundred three thousand, three hundred twenty-one".