28158568831 has 4 divisors (see below), whose sum is σ = 28555168464. Its totient is φ = 27761969200.

The previous prime is 28158568829. The next prime is 28158568847. The reversal of 28158568831 is 13886585182.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28158568831 - 2¹ = 28158568829 is a prime.

It is a super-2 number, since 2×28158568831² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28158568331) 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, 198299710 + ... + 198299851.

It is an arithmetic number, because the mean of its divisors is an integer number (7138792116).

Almost surely, 2^28158568831 is an apocalyptic number.

28158568831 is a deficient number, since it is larger than the sum of its proper divisors (396599633).

28158568831 is an equidigital number, since it uses as much as digits as its factorization.

28158568831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 396599632.

The product of its digits is 3686400, while the sum is 55.

The spelling of 28158568831 in words is "twenty-eight billion, one hundred fifty-eight million, five hundred sixty-eight thousand, eight hundred thirty-one".