28173305217 has 4 divisors (see below), whose sum is σ = 37564406960. Its totient is φ = 18782203476.

The previous prime is 28173305213. The next prime is 28173305221. The reversal of 28173305217 is 71250337182.

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 an interprime number because it is at equal distance from previous prime (28173305213) and next prime (28173305221).

It is not a de Polignac number, because 28173305217 - 2² = 28173305213 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28173305213) 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, 4695550867 + ... + 4695550872.

It is an arithmetic number, because the mean of its divisors is an integer number (9391101740).

Almost surely, 2^28173305217 is an apocalyptic number.

It is an amenable number.

28173305217 is a deficient number, since it is larger than the sum of its proper divisors (9391101743).

28173305217 is an equidigital number, since it uses as much as digits as its factorization.

28173305217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9391101742.

The product of its (nonzero) digits is 70560, while the sum is 39.

The spelling of 28173305217 in words is "twenty-eight billion, one hundred seventy-three million, three hundred five thousand, two hundred seventeen".