26806561 has 4 divisors (see below), whose sum is σ = 26828800. Its totient is φ = 26784324.

The previous prime is 26806541. The next prime is 26806583. The reversal of 26806561 is 16560862.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16560862 = 2 ⋅8280431.

It is a cyclic number.

It is not a de Polignac number, because 26806561 - 2⁹ = 26806049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (26806531) 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, 9201 + ... + 11758.

It is an arithmetic number, because the mean of its divisors is an integer number (6707200).

Almost surely, 2^26806561 is an apocalyptic number.

It is an amenable number.

26806561 is a deficient number, since it is larger than the sum of its proper divisors (22239).

26806561 is a wasteful number, since it uses less digits than its factorization.

26806561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22238.

The product of its (nonzero) digits is 17280, while the sum is 34.

The square root of 26806561 is about 5177.5052872981. The cubic root of 26806561 is about 299.2818414588.

The spelling of 26806561 in words is "twenty-six million, eight hundred six thousand, five hundred sixty-one".