21033110321 has 4 divisors (see below), whose sum is σ = 21034275444. Its totient is φ = 21031945200.

The previous prime is 21033110297. The next prime is 21033110323. The reversal of 21033110321 is 12301133012.

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 9305303296 + 11727807025 = 96464^2 + 108295^2 .

It is a cyclic number.

It is not a de Polignac number, because 21033110321 - 2²² = 21028916017 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21033110321.

It is not an unprimeable number, because it can be changed into a prime (21033110323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 555050 + ... + 591731.

It is an arithmetic number, because the mean of its divisors is an integer number (5258568861).

Almost surely, 2^21033110321 is an apocalyptic number.

It is an amenable number.

21033110321 is a deficient number, since it is larger than the sum of its proper divisors (1165123).

21033110321 is a wasteful number, since it uses less digits than its factorization.

21033110321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1165122.

The product of its (nonzero) digits is 108, while the sum is 17.

Adding to 21033110321 its reverse (12301133012), we get a palindrome (33334243333).

The spelling of 21033110321 in words is "twenty-one billion, thirty-three million, one hundred ten thousand, three hundred twenty-one".