129666539 has 4 divisors (see below), whose sum is σ = 129888024. Its totient is φ = 129445056.

The previous prime is 129666533. The next prime is 129666577. The reversal of 129666539 is 935666921.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 935666921 = 7 ⋅133666703.

It is a cyclic number.

It is not a de Polignac number, because 129666539 - 2⁸ = 129666283 is a prime.

It is a super-2 number, since 2×129666539² = 33626822672477042, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 129666493 and 129666502.

It is not an unprimeable number, because it can be changed into a prime (129666533) 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, 109862 + ... + 111035.

It is an arithmetic number, because the mean of its divisors is an integer number (32472006).

Almost surely, 2^129666539 is an apocalyptic number.

129666539 is a deficient number, since it is larger than the sum of its proper divisors (221485).

129666539 is an equidigital number, since it uses as much as digits as its factorization.

129666539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221484.

The product of its digits is 524880, while the sum is 47.

The square root of 129666539 is about 11387.1216292793. The cubic root of 129666539 is about 506.1461911013.

The spelling of 129666539 in words is "one hundred twenty-nine million, six hundred sixty-six thousand, five hundred thirty-nine".