28281831 has 16 divisors (see below), whose sum is σ = 38776320. Its totient is φ = 18325440.

The previous prime is 28281817. The next prime is 28281871. The reversal of 28281831 is 13818282.

It is not a de Polignac number, because 28281831 - 2⁶ = 28281767 is a prime.

It is a super-2 number, since 2×28281831² = 1599723929425122, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 28281792 and 28281801.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28281871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34555 + ... + 35363.

It is an arithmetic number, because the mean of its divisors is an integer number (2423520).

Almost surely, 2^28281831 is an apocalyptic number.

28281831 is a deficient number, since it is larger than the sum of its proper divisors (10494489).

28281831 is a wasteful number, since it uses less digits than its factorization.

28281831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1126.

The product of its digits is 6144, while the sum is 33.

The square root of 28281831 is about 5318.0664719426. The cubic root of 28281831 is about 304.6743132807.

The spelling of 28281831 in words is "twenty-eight million, two hundred eighty-one thousand, eight hundred thirty-one".