28287831 has 32 divisors (see below), whose sum is σ = 44658432. Its totient is φ = 15701760.

The previous prime is 28287803. The next prime is 28287839. The reversal of 28287831 is 13878282.

It is not a de Polignac number, because 28287831 - 2⁷ = 28287703 is a prime.

It is a super-2 number, since 2×28287831² = 1600402765369122, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a self number, because there is not a number n which added to its sum of digits gives 28287831.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28287839) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 99816 + ... + 100098.

It is an arithmetic number, because the mean of its divisors is an integer number (1395576).

Almost surely, 2^28287831 is an apocalyptic number.

28287831 is a deficient number, since it is larger than the sum of its proper divisors (16370601).

28287831 is a wasteful number, since it uses less digits than its factorization.

28287831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 543.

The product of its digits is 43008, while the sum is 39.

The square root of 28287831 is about 5318.6305568257. The cubic root of 28287831 is about 304.6958573434.

The spelling of 28287831 in words is "twenty-eight million, two hundred eighty-seven thousand, eight hundred thirty-one".