21210323231 has 4 divisors (see below), whose sum is σ = 21661606752. Its totient is φ = 20759039712.

The previous prime is 21210323209. The next prime is 21210323269. The reversal of 21210323231 is 13232301212.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21210323231 - 2¹⁴ = 21210306847 is a prime.

It is a super-2 number, since 2×21210323231² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210323291) 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, 225641690 + ... + 225641783.

It is an arithmetic number, because the mean of its divisors is an integer number (5415401688).

Almost surely, 2^21210323231 is an apocalyptic number.

21210323231 is a deficient number, since it is larger than the sum of its proper divisors (451283521).

21210323231 is an equidigital number, since it uses as much as digits as its factorization.

21210323231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 451283520.

The product of its (nonzero) digits is 432, while the sum is 20.

Adding to 21210323231 its reverse (13232301212), we get a palindrome (34442624443).

The spelling of 21210323231 in words is "twenty-one billion, two hundred ten million, three hundred twenty-three thousand, two hundred thirty-one".