129824221 has 2 divisors, whose sum is σ = 129824222. Its totient is φ = 129824220.

The previous prime is 129824209. The next prime is 129824239. The reversal of 129824221 is 122428921.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 98307225 + 31516996 = 9915^2 + 5614^2 .

It is a cyclic number.

It is not a de Polignac number, because 129824221 - 2¹⁷ = 129693149 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (129824021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64912110 + 64912111.

It is an arithmetic number, because the mean of its divisors is an integer number (64912111).

Almost surely, 2^129824221 is an apocalyptic number.

It is an amenable number.

129824221 is a deficient number, since it is larger than the sum of its proper divisors (1).

129824221 is an equidigital number, since it uses as much as digits as its factorization.

129824221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4608, while the sum is 31.

The square root of 129824221 is about 11394.0432244221. The cubic root of 129824221 is about 506.3512756587.

The spelling of 129824221 in words is "one hundred twenty-nine million, eight hundred twenty-four thousand, two hundred twenty-one".