26572565665 has 4 divisors (see below), whose sum is σ = 31887078804. Its totient is φ = 21258052528.

The previous prime is 26572565633. The next prime is 26572565693. The reversal of 26572565665 is 56656527562.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56656527562 = 2 ⋅28328263781.

It can be written as a sum of positive squares in 2 ways, for example, as 17605043856 + 8967521809 = 132684^2 + 94697^2 .

It is a cyclic number.

It is not a de Polignac number, because 26572565665 - 2⁵ = 26572565633 is a prime.

It is a super-2 number, since 2×26572565665² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2657256562 + ... + 2657256571.

It is an arithmetic number, because the mean of its divisors is an integer number (7971769701).

Almost surely, 2^26572565665 is an apocalyptic number.

It is an amenable number.

26572565665 is a deficient number, since it is larger than the sum of its proper divisors (5314513139).

26572565665 is an equidigital number, since it uses as much as digits as its factorization.

26572565665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5314513138.

The product of its digits is 22680000, while the sum is 55.

The spelling of 26572565665 in words is "twenty-six billion, five hundred seventy-two million, five hundred sixty-five thousand, six hundred sixty-five".