26391865 has 4 divisors (see below), whose sum is σ = 31670244. Its totient is φ = 21113488.

The previous prime is 26391853. The next prime is 26391887. The reversal of 26391865 is 56819362.

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

It can be written as a sum of positive squares in 2 ways, for example, as 11048976 + 15342889 = 3324^2 + 3917^2 .

It is a cyclic number.

It is not a de Polignac number, because 26391865 - 2⁷ = 26391737 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2639182 + ... + 2639191.

It is an arithmetic number, because the mean of its divisors is an integer number (7917561).

Almost surely, 2^26391865 is an apocalyptic number.

It is an amenable number.

26391865 is a deficient number, since it is larger than the sum of its proper divisors (5278379).

26391865 is an equidigital number, since it uses as much as digits as its factorization.

26391865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5278378.

The product of its digits is 77760, while the sum is 40.

The square root of 26391865 is about 5137.3013343583. The cubic root of 26391865 is about 297.7305230216.

The spelling of 26391865 in words is "twenty-six million, three hundred ninety-one thousand, eight hundred sixty-five".