28195391 has 4 divisors (see below), whose sum is σ = 32223312. Its totient is φ = 24167472.

The previous prime is 28195381. The next prime is 28195393. The reversal of 28195391 is 19359182.

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

It is not a de Polignac number, because 28195391 - 2⁶ = 28195327 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28195393) 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, 2013950 + ... + 2013963.

It is an arithmetic number, because the mean of its divisors is an integer number (8055828).

Almost surely, 2^28195391 is an apocalyptic number.

28195391 is a deficient number, since it is larger than the sum of its proper divisors (4027921).

28195391 is an equidigital number, since it uses as much as digits as its factorization.

28195391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4027920.

The product of its digits is 19440, while the sum is 38.

The square root of 28195391 is about 5309.9332387517. The cubic root of 28195391 is about 304.3635964313.

The spelling of 28195391 in words is "twenty-eight million, one hundred ninety-five thousand, three hundred ninety-one".