28130831 has 4 divisors (see below), whose sum is σ = 28165200. Its totient is φ = 28096464.

The previous prime is 28130827. The next prime is 28130833. The reversal of 28130831 is 13803182.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13803182 = 2 ⋅6901591.

It is a cyclic number.

It is not a de Polignac number, because 28130831 - 2² = 28130827 is a prime.

It is a super-2 number, since 2×28130831² = 1582687305501122, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28130831.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28130833) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15926 + ... + 17603.

It is an arithmetic number, because the mean of its divisors is an integer number (7041300).

Almost surely, 2^28130831 is an apocalyptic number.

28130831 is a deficient number, since it is larger than the sum of its proper divisors (34369).

28130831 is an equidigital number, since it uses as much as digits as its factorization.

28130831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34368.

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 28130831 is about 5303.8505823600. The cubic root of 28130831 is about 304.1311148123.

The spelling of 28130831 in words is "twenty-eight million, one hundred thirty thousand, eight hundred thirty-one".