28191569 has 4 divisors (see below), whose sum is σ = 32218944. Its totient is φ = 24164196.

The previous prime is 28191547. The next prime is 28191571. The reversal of 28191569 is 96519182.

It is a happy number.

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.

It is a de Polignac number, because none of the positive numbers 2^k-28191569 is a prime.

It is a super-2 number, since 2×28191569² = 1589529125363522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28191529) 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, 2013677 + ... + 2013690.

It is an arithmetic number, because the mean of its divisors is an integer number (8054736).

Almost surely, 2^28191569 is an apocalyptic number.

It is an amenable number.

28191569 is a deficient number, since it is larger than the sum of its proper divisors (4027375).

28191569 is an equidigital number, since it uses as much as digits as its factorization.

28191569 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4027374.

The product of its digits is 38880, while the sum is 41.

The square root of 28191569 is about 5309.5733350242. The cubic root of 28191569 is about 304.3498432351.

The spelling of 28191569 in words is "twenty-eight million, one hundred ninety-one thousand, five hundred sixty-nine".