215205017129 has 4 divisors (see below), whose sum is σ = 215205984084. Its totient is φ = 215204050176.

The previous prime is 215205017047. The next prime is 215205017147. The reversal of 215205017129 is 921710502512.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 158726544025 + 56478473104 = 398405^2 + 237652^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-215205017129 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (215205017029) 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, 37469 + ... + 657125.

It is an arithmetic number, because the mean of its divisors is an integer number (53801496021).

Almost surely, 2^215205017129 is an apocalyptic number.

It is an amenable number.

215205017129 is a deficient number, since it is larger than the sum of its proper divisors (966955).

215205017129 is an equidigital number, since it uses as much as digits as its factorization.

215205017129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 966954.

The product of its (nonzero) digits is 12600, while the sum is 35.

The spelling of 215205017129 in words is "two hundred fifteen billion, two hundred five million, seventeen thousand, one hundred twenty-nine".