129823217 has 2 divisors, whose sum is σ = 129823218. Its totient is φ = 129823216.

The previous prime is 129823193. The next prime is 129823223. The reversal of 129823217 is 712328921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 112550881 + 17272336 = 10609^2 + 4156^2 .

It is a cyclic number.

It is not a de Polignac number, because 129823217 - 2¹² = 129819121 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (129823277) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64911608 + 64911609.

It is an arithmetic number, because the mean of its divisors is an integer number (64911609).

Almost surely, 2^129823217 is an apocalyptic number.

It is an amenable number.

129823217 is a deficient number, since it is larger than the sum of its proper divisors (1).

129823217 is an equidigital number, since it uses as much as digits as its factorization.

129823217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12096, while the sum is 35.

The square root of 129823217 is about 11393.9991662278. Note that the first 3 decimals coincide. The cubic root of 129823217 is about 506.3499703605.

The spelling of 129823217 in words is "one hundred twenty-nine million, eight hundred twenty-three thousand, two hundred seventeen".