28111969 has 4 divisors (see below), whose sum is σ = 28710144. Its totient is φ = 27513796.

The previous prime is 28111961. The next prime is 28111973. The reversal of 28111969 is 96911182.

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: 96911182 = 2 ⋅48455591.

It is a cyclic number.

It is not a de Polignac number, because 28111969 - 2³ = 28111961 is a prime.

It is a super-2 number, since 2×28111969² = 1580565602113922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28111961) 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, 299017 + ... + 299110.

It is an arithmetic number, because the mean of its divisors is an integer number (7177536).

Almost surely, 2^28111969 is an apocalyptic number.

It is an amenable number.

28111969 is a deficient number, since it is larger than the sum of its proper divisors (598175).

28111969 is an equidigital number, since it uses as much as digits as its factorization.

28111969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 598174.

The product of its digits is 7776, while the sum is 37.

The square root of 28111969 is about 5302.0721420969. The cubic root of 28111969 is about 304.0631253088.

The spelling of 28111969 in words is "twenty-eight million, one hundred eleven thousand, nine hundred sixty-nine".