21102320321 has 4 divisors (see below), whose sum is σ = 21295919700. Its totient is φ = 20908720944.

The previous prime is 21102320243. The next prime is 21102320359. The reversal of 21102320321 is 12302320112.

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 17151569296 + 3950751025 = 130964^2 + 62855^2 .

It is a cyclic number.

It is not a de Polignac number, because 21102320321 - 2²² = 21098126017 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 21102320321.

It is not an unprimeable number, because it can be changed into a prime (21102320621) 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, 96799526 + ... + 96799743.

It is an arithmetic number, because the mean of its divisors is an integer number (5323979925).

Almost surely, 2^21102320321 is an apocalyptic number.

It is an amenable number.

21102320321 is a deficient number, since it is larger than the sum of its proper divisors (193599379).

21102320321 is a wasteful number, since it uses less digits than its factorization.

21102320321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 193599378.

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 21102320321 its reverse (12302320112), we get a palindrome (33404640433).

The spelling of 21102320321 in words is "twenty-one billion, one hundred two million, three hundred twenty thousand, three hundred twenty-one".