31123 has 2 divisors, whose sum is σ = 31124. Its totient is φ = 31122.

The previous prime is 31121. The next prime is 31139. The reversal of 31123 is 32113.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 31123 - 2¹ = 31121 is a prime.

It is a super-2 number, since 2×31123² = 1937282258, which contains 22 as substring.

Together with 31121, it forms a pair of twin primes.

It is an Ulam number.

It is not a weakly prime, because it can be changed into another prime (31121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15561 + 15562.

It is an arithmetic number, because the mean of its divisors is an integer number (15562).

2³¹¹²³ is an apocalyptic number.

31123 is a deficient number, since it is larger than the sum of its proper divisors (1).

31123 is an equidigital number, since it uses as much as digits as its factorization.

31123 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18, while the sum is 10.

The square root of 31123 is about 176.4171193507. The cubic root of 31123 is about 31.4552989876.

Subtracting from 31123 its sum of digits (10), we obtain a palindrome (31113).

Adding to 31123 its reverse (32113), we get a palindrome (63236).

Subtracting 31123 from its reverse (32113), we obtain a triangular number (990 = T₄₄).

The spelling of 31123 in words is "thirty-one thousand, one hundred twenty-three".