129457217 has 4 divisors (see below), whose sum is σ = 131899860. Its totient is φ = 127014576.

The previous prime is 129457201. The next prime is 129457249. The reversal of 129457217 is 712754921.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 712754921 = 8971 ⋅79451.

It can be written as a sum of positive squares in 2 ways, for example, as 99820081 + 29637136 = 9991^2 + 5444^2 .

It is a cyclic number.

It is not a de Polignac number, because 129457217 - 2⁴ = 129457201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129457277) 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, 1221242 + ... + 1221347.

It is an arithmetic number, because the mean of its divisors is an integer number (32974965).

Almost surely, 2^129457217 is an apocalyptic number.

It is an amenable number.

129457217 is a deficient number, since it is larger than the sum of its proper divisors (2442643).

129457217 is an equidigital number, since it uses as much as digits as its factorization.

129457217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2442642.

The product of its digits is 35280, while the sum is 38.

The square root of 129457217 is about 11377.9267443590. The cubic root of 129457217 is about 505.8736854476.

The spelling of 129457217 in words is "one hundred twenty-nine million, four hundred fifty-seven thousand, two hundred seventeen".