28125231 has 4 divisors (see below), whose sum is σ = 37500312. Its totient is φ = 18750152.

The previous prime is 28125203. The next prime is 28125233. The reversal of 28125231 is 13252182.

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 28125231 - 2⁷ = 28125103 is a prime.

It is a super-2 number, since 2×28125231² = 1582057237606722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28125233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4687536 + ... + 4687541.

It is an arithmetic number, because the mean of its divisors is an integer number (9375078).

Almost surely, 2^28125231 is an apocalyptic number.

28125231 is a deficient number, since it is larger than the sum of its proper divisors (9375081).

28125231 is an equidigital number, since it uses as much as digits as its factorization.

28125231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9375080.

The product of its digits is 960, while the sum is 24.

The square root of 28125231 is about 5303.3226377432. The cubic root of 28125231 is about 304.1109323623.

The spelling of 28125231 in words is "twenty-eight million, one hundred twenty-five thousand, two hundred thirty-one".