21321331231 has 2 divisors, whose sum is σ = 21321331232. Its totient is φ = 21321331230.

The previous prime is 21321331217. The next prime is 21321331261. The reversal of 21321331231 is 13213312312.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21321331231 is a prime.

It is a super-2 number, since 2×21321331231² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21321331261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10660665615 + 10660665616.

It is an arithmetic number, because the mean of its divisors is an integer number (10660665616).

Almost surely, 2^21321331231 is an apocalyptic number.

21321331231 is a deficient number, since it is larger than the sum of its proper divisors (1).

21321331231 is an equidigital number, since it uses as much as digits as its factorization.

21321331231 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 648, while the sum is 22.

Adding to 21321331231 its reverse (13213312312), we get a palindrome (34534643543).

It can be divided in two parts, 2 and 1321331231, that multiplied together give a palindrome (2642662462).

The spelling of 21321331231 in words is "twenty-one billion, three hundred twenty-one million, three hundred thirty-one thousand, two hundred thirty-one".