21031231223 has 4 divisors (see below), whose sum is σ = 21075138240. Its totient is φ = 20987324208.

The previous prime is 21031231217. The next prime is 21031231229. The reversal of 21031231223 is 32213213012.

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

It is an interprime number because it is at equal distance from previous prime (21031231217) and next prime (21031231229).

It is a cyclic number.

It is not a de Polignac number, because 21031231223 - 2¹⁴ = 21031214839 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21031231195 and 21031231204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21031231229) 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, 21952790 + ... + 21953747.

It is an arithmetic number, because the mean of its divisors is an integer number (5268784560).

Almost surely, 2^21031231223 is an apocalyptic number.

21031231223 is a deficient number, since it is larger than the sum of its proper divisors (43907017).

21031231223 is an equidigital number, since it uses as much as digits as its factorization.

21031231223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43907016.

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

Adding to 21031231223 its reverse (32213213012), we get a palindrome (53244444235).

The spelling of 21031231223 in words is "twenty-one billion, thirty-one million, two hundred thirty-one thousand, two hundred twenty-three".