28155430931 has 4 divisors (see below), whose sum is σ = 28156125864. Its totient is φ = 28154736000.

The previous prime is 28155430921. The next prime is 28155430937. The reversal of 28155430931 is 13903455182.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13903455182 = 2 ⋅6951727591.

It is a cyclic number.

It is not a de Polignac number, because 28155430931 - 2³⁴ = 10975561747 is a prime.

It is a super-2 number, since 2×28155430931² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28155430937) 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, 282665 + ... + 369066.

It is an arithmetic number, because the mean of its divisors is an integer number (7039031466).

Almost surely, 2^28155430931 is an apocalyptic number.

28155430931 is a deficient number, since it is larger than the sum of its proper divisors (694933).

28155430931 is an equidigital number, since it uses as much as digits as its factorization.

28155430931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 694932.

The product of its (nonzero) digits is 129600, while the sum is 41.

The spelling of 28155430931 in words is "twenty-eight billion, one hundred fifty-five million, four hundred thirty thousand, nine hundred thirty-one".