28131559 has 4 divisors (see below), whose sum is σ = 28196080. Its totient is φ = 28067040.

The previous prime is 28131557. The next prime is 28131569. The reversal of 28131559 is 95513182.

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 28131559 - 2¹ = 28131557 is a prime.

It is a super-2 number, since 2×28131559² = 1582769223540962, which 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 (28131557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31602 + ... + 32479.

It is an arithmetic number, because the mean of its divisors is an integer number (7049020).

Almost surely, 2^28131559 is an apocalyptic number.

28131559 is a deficient number, since it is larger than the sum of its proper divisors (64521).

28131559 is an equidigital number, since it uses as much as digits as its factorization.

28131559 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64520.

The product of its digits is 10800, while the sum is 34.

The square root of 28131559 is about 5303.9192113003. The cubic root of 28131559 is about 304.1337383340.

The spelling of 28131559 in words is "twenty-eight million, one hundred thirty-one thousand, five hundred fifty-nine".