26405331665 has 8 divisors (see below), whose sum is σ = 32284254888. Its totient is φ = 20725694080.

The previous prime is 26405331653. The next prime is 26405331709. The reversal of 26405331665 is 56613350462.

It can be written as a sum of positive squares in 4 ways, for example, as 3811333696 + 22593997969 = 61736^2 + 150313^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 26405331665 - 2³⁰ = 25331589841 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49821116 + ... + 49821645.

It is an arithmetic number, because the mean of its divisors is an integer number (4035531861).

Almost surely, 2^26405331665 is an apocalyptic number.

It is an amenable number.

26405331665 is a deficient number, since it is larger than the sum of its proper divisors (5878923223).

26405331665 is an equidigital number, since it uses as much as digits as its factorization.

26405331665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99642819.

The product of its (nonzero) digits is 388800, while the sum is 41.

The spelling of 26405331665 in words is "twenty-six billion, four hundred five million, three hundred thirty-one thousand, six hundred sixty-five".