28930191809 has 4 divisors (see below), whose sum is σ = 29927784660. Its totient is φ = 27932598960.

The previous prime is 28930191803. The next prime is 28930191811. The reversal of 28930191809 is 90819103982.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90819103982 = 2 ⋅45409551991.

It can be written as a sum of positive squares in 2 ways, for example, as 16762998784 + 12167193025 = 129472^2 + 110305^2 .

It is a cyclic number.

It is not a de Polignac number, because 28930191809 - 2²⁰ = 28929143233 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28930191803) 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, 498796382 + ... + 498796439.

It is an arithmetic number, because the mean of its divisors is an integer number (7481946165).

Almost surely, 2^28930191809 is an apocalyptic number.

28930191809 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

28930191809 is a deficient number, since it is larger than the sum of its proper divisors (997592851).

28930191809 is an equidigital number, since it uses as much as digits as its factorization.

28930191809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 997592850.

The product of its (nonzero) digits is 279936, while the sum is 50.

The spelling of 28930191809 in words is "twenty-eight billion, nine hundred thirty million, one hundred ninety-one thousand, eight hundred nine".