28131287 has 8 divisors (see below), whose sum is σ = 28759104. Its totient is φ = 27507168.

The previous prime is 28131283. The next prime is 28131307. The reversal of 28131287 is 78213182.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28131287 - 2² = 28131283 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 (28131283) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19058 + ... + 20480.

It is an arithmetic number, because the mean of its divisors is an integer number (3594888).

Almost surely, 2^28131287 is an apocalyptic number.

28131287 is a deficient number, since it is larger than the sum of its proper divisors (627817).

28131287 is a wasteful number, since it uses less digits than its factorization.

28131287 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1849.

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

The square root of 28131287 is about 5303.8935698221. The cubic root of 28131287 is about 304.1327581224.

The spelling of 28131287 in words is "twenty-eight million, one hundred thirty-one thousand, two hundred eighty-seven".