129257305 has 4 divisors (see below), whose sum is σ = 155108772. Its totient is φ = 103405840.

The previous prime is 129257299. The next prime is 129257327. The reversal of 129257305 is 503752921.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 503752921 = 7 ⋅71964703.

It can be written as a sum of positive squares in 2 ways, for example, as 17172736 + 112084569 = 4144^2 + 10587^2 .

It is a de Polignac number, because none of the positive numbers 2^k-129257305 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12925726 + ... + 12925735.

It is an arithmetic number, because the mean of its divisors is an integer number (38777193).

Almost surely, 2^129257305 is an apocalyptic number.

It is an amenable number.

129257305 is a deficient number, since it is larger than the sum of its proper divisors (25851467).

129257305 is an equidigital number, since it uses as much as digits as its factorization.

129257305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25851466.

The product of its (nonzero) digits is 18900, while the sum is 34.

The square root of 129257305 is about 11369.1382698954. The cubic root of 129257305 is about 505.6131558213.

The spelling of 129257305 in words is "one hundred twenty-nine million, two hundred fifty-seven thousand, three hundred five".