28191830091 has 4 divisors (see below), whose sum is σ = 37589106792. Its totient is φ = 18794553392.

The previous prime is 28191830083. The next prime is 28191830137. The reversal of 28191830091 is 19003819182.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28191830091 - 2³ = 28191830083 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28191830021) 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, 4698638346 + ... + 4698638351.

It is an arithmetic number, because the mean of its divisors is an integer number (9397276698).

Almost surely, 2^28191830091 is an apocalyptic number.

28191830091 is a deficient number, since it is larger than the sum of its proper divisors (9397276701).

28191830091 is an equidigital number, since it uses as much as digits as its factorization.

28191830091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9397276700.

The product of its (nonzero) digits is 31104, while the sum is 42.

The spelling of 28191830091 in words is "twenty-eight billion, one hundred ninety-one million, eight hundred thirty thousand, ninety-one".