28112261 has 4 divisors (see below), whose sum is σ = 28588800. Its totient is φ = 27635724.

The previous prime is 28112221. The next prime is 28112291. The reversal of 28112261 is 16221182.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16221182 = 2 ⋅8110591.

It is a cyclic number.

It is not a de Polignac number, because 28112261 - 2¹⁸ = 27850117 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28112221) 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, 238181 + ... + 238298.

It is an arithmetic number, because the mean of its divisors is an integer number (7147200).

Almost surely, 2^28112261 is an apocalyptic number.

It is an amenable number.

28112261 is a deficient number, since it is larger than the sum of its proper divisors (476539).

28112261 is an equidigital number, since it uses as much as digits as its factorization.

28112261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 476538.

The product of its digits is 384, while the sum is 23.

The square root of 28112261 is about 5302.0996784293. The cubic root of 28112261 is about 304.0641780765.

The spelling of 28112261 in words is "twenty-eight million, one hundred twelve thousand, two hundred sixty-one".