129931 has 4 divisors (see below), whose sum is σ = 137592. Its totient is φ = 122272.

The previous prime is 129919. The next prime is 129937. The reversal of 129931 is 139921.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 129931 - 2⁷ = 129803 is a prime.

It is a super-2 number, since 2×129931² = 33764129522, which contains 22 as substring.

It is a Duffinian number.

129931 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 129896 and 129905.

It is not an unprimeable number, because it can be changed into a prime (129937) 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, 3805 + ... + 3838.

It is an arithmetic number, because the mean of its divisors is an integer number (34398).

2¹²⁹⁹³¹ is an apocalyptic number.

129931 is a deficient number, since it is larger than the sum of its proper divisors (7661).

129931 is an equidigital number, since it uses as much as digits as its factorization.

129931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7660.

The product of its digits is 486, while the sum is 25.

The square root of 129931 is about 360.4594290624. The cubic root of 129931 is about 50.6490060409.

The spelling of 129931 in words is "one hundred twenty-nine thousand, nine hundred thirty-one".