31129 has 4 divisors (see below), whose sum is σ = 35584. Its totient is φ = 26676.

The previous prime is 31123. The next prime is 31139. The reversal of 31129 is 92113.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 92113 = 7 ⋅13159.

It is a cyclic number.

It is not a de Polignac number, because 31129 - 2³ = 31121 is a prime.

It is a Duffinian number.

It is a plaindrome in base 13 and base 16.

It is not an unprimeable number, because it can be changed into a prime (31121) 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, 2217 + ... + 2230.

It is an arithmetic number, because the mean of its divisors is an integer number (8896).

2³¹¹²⁹ is an apocalyptic number.

It is an amenable number.

31129 is a deficient number, since it is larger than the sum of its proper divisors (4455).

31129 is an equidigital number, since it uses as much as digits as its factorization.

31129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4454.

The product of its digits is 54, while the sum is 16.

The square root of 31129 is about 176.4341236836. The cubic root of 31129 is about 31.4573202116.

Subtracting from 31129 its sum of digits (16), we obtain a palindrome (31113).

The spelling of 31129 in words is "thirty-one thousand, one hundred twenty-nine".