28197273917 has 4 divisors (see below), whose sum is σ = 28201016700. Its totient is φ = 28193531136.

The previous prime is 28197273899. The next prime is 28197273977. The reversal of 28197273917 is 71937279182.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 71937279182 = 2 ⋅35968639591.

It can be written as a sum of positive squares in 2 ways, for example, as 25963199161 + 2234074756 = 161131^2 + 47266^2 .

It is a cyclic number.

It is not a de Polignac number, because 28197273917 - 2¹⁴ = 28197257533 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28197273977) 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, 1860068 + ... + 1875165.

It is an arithmetic number, because the mean of its divisors is an integer number (7050254175).

Almost surely, 2^28197273917 is an apocalyptic number.

It is an amenable number.

28197273917 is a deficient number, since it is larger than the sum of its proper divisors (3742783).

28197273917 is an equidigital number, since it uses as much as digits as its factorization.

28197273917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3742782.

The product of its digits is 2667168, while the sum is 56.

The spelling of 28197273917 in words is "twenty-eight billion, one hundred ninety-seven million, two hundred seventy-three thousand, nine hundred seventeen".