129689531 has 2 divisors, whose sum is σ = 129689532. Its totient is φ = 129689530.

The previous prime is 129689513. The next prime is 129689533. The reversal of 129689531 is 135986921.

It is a happy number.

Together with previous prime (129689513) 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 129689531 - 2⁶ = 129689467 is a prime.

It is a super-2 number, since 2×129689531² = 33638748901999922, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 129689533, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (129689533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64844765 + 64844766.

It is an arithmetic number, because the mean of its divisors is an integer number (64844766).

Almost surely, 2^129689531 is an apocalyptic number.

129689531 is a deficient number, since it is larger than the sum of its proper divisors (1).

129689531 is an equidigital number, since it uses as much as digits as its factorization.

129689531 is an evil number, because the sum of its binary digits is even.

The product of its digits is 116640, while the sum is 44.

The square root of 129689531 is about 11388.1311460661. The cubic root of 129689531 is about 506.1761053350.

The spelling of 129689531 in words is "one hundred twenty-nine million, six hundred eighty-nine thousand, five hundred thirty-one".