139831 has 2 divisors, whose sum is σ = 139832. Its totient is φ = 139830.

The previous prime is 139813. The next prime is 139837. The reversal of 139831 is 138931.

Together with previous prime (139813) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 139831 - 2⁷ = 139703 is a prime.

It is a super-2 number, since 2×139831² = 39105417122, which contains 22 as substring.

It is equal to p₁₂₉₉₄ and since 139831 and 12994 have the same sum of digits, it is a Honaker prime.

It is a plaindrome in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 139796 and 139805.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (139837) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69915 + 69916.

It is an arithmetic number, because the mean of its divisors is an integer number (69916).

2¹³⁹⁸³¹ is an apocalyptic number.

139831 is the 237-th centered pentagonal number.

139831 is a deficient number, since it is larger than the sum of its proper divisors (1).

139831 is an equidigital number, since it uses as much as digits as its factorization.

139831 is an evil number, because the sum of its binary digits is even.

The product of its digits is 648, while the sum is 25.

The square root of 139831 is about 373.9398347328. The cubic root of 139831 is about 51.9040389985.

Subtracting from 139831 its reverse (138931), we obtain a square (900 = 30²).

The spelling of 139831 in words is "one hundred thirty-nine thousand, eight hundred thirty-one".