28190791 has 4 divisors (see below), whose sum is σ = 28464592. Its totient is φ = 27916992.

The previous prime is 28190759. The next prime is 28190803. The reversal of 28190791 is 19709182.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19709182 = 2 ⋅9854591.

It is a cyclic number.

It is not a de Polignac number, because 28190791 - 2⁵ = 28190759 is a prime.

It is the 5310-th Hogben number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28190791.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28190891) by changing a digit.

It is a nontrivial repunit in base 5309.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 136746 + ... + 136951.

It is an arithmetic number, because the mean of its divisors is an integer number (7116148).

Almost surely, 2^28190791 is an apocalyptic number.

28190791 is a deficient number, since it is larger than the sum of its proper divisors (273801).

28190791 is a wasteful number, since it uses less digits than its factorization.

28190791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 273800.

The product of its (nonzero) digits is 9072, while the sum is 37.

The square root of 28190791 is about 5309.5000706281. The cubic root of 28190791 is about 304.3470435049.

The spelling of 28190791 in words is "twenty-eight million, one hundred ninety thousand, seven hundred ninety-one".