28531261357 has 4 divisors (see below), whose sum is σ = 28599031996. Its totient is φ = 28463490720.

The previous prime is 28531261349. The next prime is 28531261379. The reversal of 28531261357 is 75316213582.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 75316213582 = 2 ⋅37658106791.

It can be written as a sum of positive squares in 2 ways, for example, as 1887554916 + 26643706441 = 43446^2 + 163229^2 .

It is a cyclic number.

It is not a de Polignac number, because 28531261357 - 2³ = 28531261349 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 (28531261397) 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, 33884688 + ... + 33885529.

It is an arithmetic number, because the mean of its divisors is an integer number (7149757999).

Almost surely, 2^28531261357 is an apocalyptic number.

It is an amenable number.

28531261357 is a deficient number, since it is larger than the sum of its proper divisors (67770639).

28531261357 is an equidigital number, since it uses as much as digits as its factorization.

28531261357 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67770638.

The product of its digits is 302400, while the sum is 43.

The spelling of 28531261357 in words is "twenty-eight billion, five hundred thirty-one million, two hundred sixty-one thousand, three hundred fifty-seven".