129216361 has 4 divisors (see below), whose sum is σ = 131334724. Its totient is φ = 127098000.

The previous prime is 129216349. The next prime is 129216377. The reversal of 129216361 is 163612921.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 60840000 + 68376361 = 7800^2 + 8269^2 .

It is a cyclic number.

It is not a de Polignac number, because 129216361 - 2¹³ = 129208169 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129216331) 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, 1059090 + ... + 1059211.

It is an arithmetic number, because the mean of its divisors is an integer number (32833681).

Almost surely, 2^129216361 is an apocalyptic number.

It is an amenable number.

129216361 is a deficient number, since it is larger than the sum of its proper divisors (2118363).

129216361 is an equidigital number, since it uses as much as digits as its factorization.

129216361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2118362.

The product of its digits is 3888, while the sum is 31.

The square root of 129216361 is about 11367.3374631001. The cubic root of 129216361 is about 505.5597635809.

The spelling of 129216361 in words is "one hundred twenty-nine million, two hundred sixteen thousand, three hundred sixty-one".