28191399 has 16 divisors (see below), whose sum is σ = 40061952. Its totient is φ = 17592608.

The previous prime is 28191379. The next prime is 28191403. The reversal of 28191399 is 99319182.

It is not a de Polignac number, because 28191399 - 2⁹ = 28190887 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28191399.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28191329) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1104 + ... + 7589.

It is an arithmetic number, because the mean of its divisors is an integer number (2503872).

Almost surely, 2^28191399 is an apocalyptic number.

28191399 is a deficient number, since it is larger than the sum of its proper divisors (11870553).

28191399 is a wasteful number, since it uses less digits than its factorization.

28191399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8766.

The product of its digits is 34992, while the sum is 42.

The square root of 28191399 is about 5309.5573261808. The cubic root of 28191399 is about 304.3492314733.

The spelling of 28191399 in words is "twenty-eight million, one hundred ninety-one thousand, three hundred ninety-nine".