31139 has 2 divisors, whose sum is σ = 31140. Its totient is φ = 31138.

The previous prime is 31123. The next prime is 31147. The reversal of 31139 is 93113.

It is a strong prime.

It is an emirp because it is prime and its reverse (93113) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31139 - 2⁴ = 31123 is a prime.

It is a plaindrome in base 13.

It is not a weakly prime, because it can be changed into another prime (31159) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15569 + 15570.

It is an arithmetic number, because the mean of its divisors is an integer number (15570).

2³¹¹³⁹ is an apocalyptic number.

31139 is a deficient number, since it is larger than the sum of its proper divisors (1).

31139 is an equidigital number, since it uses as much as digits as its factorization.

31139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 81, while the sum is 17.

The square root of 31139 is about 176.4624605971. The cubic root of 31139 is about 31.4606883413.

The spelling of 31139 in words is "thirty-one thousand, one hundred thirty-nine".