21135231321 has 8 divisors (see below), whose sum is σ = 28181196000. Its totient is φ = 14089710432.

The previous prime is 21135231319. The next prime is 21135231329. The reversal of 21135231321 is 12313253112.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21135231321 - 2¹ = 21135231319 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21135231291 and 21135231300.

It is not an unprimeable number, because it can be changed into a prime (21135231329) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23430 + ... + 206928.

It is an arithmetic number, because the mean of its divisors is an integer number (3522649500).

Almost surely, 2^21135231321 is an apocalyptic number.

It is an amenable number.

21135231321 is a deficient number, since it is larger than the sum of its proper divisors (7045964679).

21135231321 is a wasteful number, since it uses less digits than its factorization.

21135231321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221895.

The product of its digits is 1080, while the sum is 24.

Adding to 21135231321 its reverse (12313253112), we get a palindrome (33448484433).

The spelling of 21135231321 in words is "twenty-one billion, one hundred thirty-five million, two hundred thirty-one thousand, three hundred twenty-one".