28287131 has 4 divisors (see below), whose sum is σ = 28325064. Its totient is φ = 28249200.

The previous prime is 28287113. The next prime is 28287139. The reversal of 28287131 is 13178282.

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 28287131 - 2¹⁸ = 28024987 is a prime.

It is a super-2 number, since 2×28287131² = 1600323560422322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28287139) 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, 17825 + ... + 19346.

It is an arithmetic number, because the mean of its divisors is an integer number (7081266).

Almost surely, 2^28287131 is an apocalyptic number.

28287131 is a deficient number, since it is larger than the sum of its proper divisors (37933).

28287131 is an equidigital number, since it uses as much as digits as its factorization.

28287131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37932.

The product of its digits is 5376, while the sum is 32.

The square root of 28287131 is about 5318.5647500054. The cubic root of 28287131 is about 304.6933440264.

The spelling of 28287131 in words is "twenty-eight million, two hundred eighty-seven thousand, one hundred thirty-one".