26540015561 has 4 divisors (see below), whose sum is σ = 26903577492. Its totient is φ = 26176453632.

The previous prime is 26540015539. The next prime is 26540015581. The reversal of 26540015561 is 16551004562.

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 11526169600 + 15013845961 = 107360^2 + 122531^2 .

It is a cyclic number.

It is not a de Polignac number, because 26540015561 - 2¹⁸ = 26539753417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (26540015581) 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, 181780856 + ... + 181781001.

It is an arithmetic number, because the mean of its divisors is an integer number (6725894373).

Almost surely, 2^26540015561 is an apocalyptic number.

It is an amenable number.

26540015561 is a deficient number, since it is larger than the sum of its proper divisors (363561931).

26540015561 is an equidigital number, since it uses as much as digits as its factorization.

26540015561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 363561930.

The product of its (nonzero) digits is 36000, while the sum is 35.

It can be divided in two parts, 2654001 and 5561, that added together give a palindrome (2659562).

The spelling of 26540015561 in words is "twenty-six billion, five hundred forty million, fifteen thousand, five hundred sixty-one".