28961257209 has 4 divisors (see below), whose sum is σ = 38615009616. Its totient is φ = 19307504804.

The previous prime is 28961257177. The next prime is 28961257217. The reversal of 28961257209 is 90275216982.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 28961257209 - 2⁵ = 28961257177 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28961257219) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4826876199 + ... + 4826876204.

It is an arithmetic number, because the mean of its divisors is an integer number (9653752404).

Almost surely, 2^28961257209 is an apocalyptic number.

It is an amenable number.

28961257209 is a deficient number, since it is larger than the sum of its proper divisors (9653752407).

28961257209 is an equidigital number, since it uses as much as digits as its factorization.

28961257209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9653752406.

The product of its (nonzero) digits is 1088640, while the sum is 51.

The spelling of 28961257209 in words is "twenty-eight billion, nine hundred sixty-one million, two hundred fifty-seven thousand, two hundred nine".