129085817 has 4 divisors (see below), whose sum is σ = 147526656. Its totient is φ = 110644980.

The previous prime is 129085813. The next prime is 129085841. The reversal of 129085817 is 718580921.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 718580921 = 4349 ⋅165229.

It is a cyclic number.

It is not a de Polignac number, because 129085817 - 2² = 129085813 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129085813) 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, 9220409 + ... + 9220422.

It is an arithmetic number, because the mean of its divisors is an integer number (36881664).

Almost surely, 2^129085817 is an apocalyptic number.

It is an amenable number.

129085817 is a deficient number, since it is larger than the sum of its proper divisors (18440839).

129085817 is an equidigital number, since it uses as much as digits as its factorization.

129085817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18440838.

The product of its (nonzero) digits is 40320, while the sum is 41.

The square root of 129085817 is about 11361.5939462736. The cubic root of 129085817 is about 505.3894548289.

The spelling of 129085817 in words is "one hundred twenty-nine million, eighty-five thousand, eight hundred seventeen".