129643321 has 2 divisors, whose sum is σ = 129643322. Its totient is φ = 129643320.

The previous prime is 129643307. The next prime is 129643331. The reversal of 129643321 is 123346921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 98406400 + 31236921 = 9920^2 + 5589^2 .

It is an emirp because it is prime and its reverse (123346921) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 129643321 - 2⁷ = 129643193 is a prime.

It is not a weakly prime, because it can be changed into another prime (129643331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64821660 + 64821661.

It is an arithmetic number, because the mean of its divisors is an integer number (64821661).

Almost surely, 2^129643321 is an apocalyptic number.

It is an amenable number.

129643321 is a deficient number, since it is larger than the sum of its proper divisors (1).

129643321 is an equidigital number, since it uses as much as digits as its factorization.

129643321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 31.

The square root of 129643321 is about 11386.1020986113. The cubic root of 129643321 is about 506.1159792367.

The spelling of 129643321 in words is "one hundred twenty-nine million, six hundred forty-three thousand, three hundred twenty-one".