28581231 has 8 divisors (see below), whose sum is σ = 43552384. Its totient is φ = 16332120.

The previous prime is 28581229. The next prime is 28581239. The reversal of 28581231 is 13218582.

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

It is not a de Polignac number, because 28581231 - 2¹ = 28581229 is a prime.

It is a super-2 number, since 2×28581231² = 1633773530950722, 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 (28581239) 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, 680485 + ... + 680526.

It is an arithmetic number, because the mean of its divisors is an integer number (5444048).

Almost surely, 2^28581231 is an apocalyptic number.

28581231 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

28581231 is a deficient number, since it is larger than the sum of its proper divisors (14971153).

28581231 is a wasteful number, since it uses less digits than its factorization.

28581231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1361021.

The product of its digits is 3840, while the sum is 30.

The square root of 28581231 is about 5346.1416928473. The cubic root of 28581231 is about 305.7456663215.

The spelling of 28581231 in words is "twenty-eight million, five hundred eighty-one thousand, two hundred thirty-one".