31123231 has 4 divisors (see below), whose sum is σ = 31134672. Its totient is φ = 31111792.

The previous prime is 31123229. The next prime is 31123241. The reversal of 31123231 is 13232113.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 13232113 = 19 ⋅696427.

It is a cyclic number.

It is not a de Polignac number, because 31123231 - 2¹ = 31123229 is a prime.

It is a super-2 number, since 2×31123231² = 1937311015758722, which 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 (31123241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 966 + ... + 7948.

It is an arithmetic number, because the mean of its divisors is an integer number (7783668).

Almost surely, 2^31123231 is an apocalyptic number.

31123231 is a deficient number, since it is larger than the sum of its proper divisors (11441).

31123231 is an equidigital number, since it uses as much as digits as its factorization.

31123231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11440.

The product of its digits is 108, while the sum is 16.

The square root of 31123231 is about 5578.8198572816. The cubic root of 31123231 is about 314.5537680951.

Adding to 31123231 its reverse (13232113), we get a palindrome (44355344).

The spelling of 31123231 in words is "thirty-one million, one hundred twenty-three thousand, two hundred thirty-one".