31231021223 has 4 divisors (see below), whose sum is σ = 31234734840. Its totient is φ = 31227307608.

The previous prime is 31231021193. The next prime is 31231021253. The reversal of 31231021223 is 32212013213.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 32212013213 = 109 ⋅295523057.

It is an interprime number because it is at equal distance from previous prime (31231021193) and next prime (31231021253).

It is a cyclic number.

It is not a de Polignac number, because 31231021223 - 2¹² = 31231017127 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31231021195 and 31231021204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31231021253) 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, 1844165 + ... + 1861022.

It is an arithmetic number, because the mean of its divisors is an integer number (7808683710).

Almost surely, 2^31231021223 is an apocalyptic number.

31231021223 is a deficient number, since it is larger than the sum of its proper divisors (3713617).

31231021223 is an equidigital number, since it uses as much as digits as its factorization.

31231021223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3713616.

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

Adding to 31231021223 its reverse (32212013213), we get a palindrome (63443034436).

The spelling of 31231021223 in words is "thirty-one billion, two hundred thirty-one million, twenty-one thousand, two hundred twenty-three".