26985815897 has 4 divisors (see below), whose sum is σ = 26986151220. Its totient is φ = 26985480576.

The previous prime is 26985815887. The next prime is 26985815951. The reversal of 26985815897 is 79851858962.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 5579492416 + 21406323481 = 74696^2 + 146309^2 .

It is a cyclic number.

It is not a de Polignac number, because 26985815897 - 2⁸ = 26985815641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (26985815807) 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, 33533 + ... + 234725.

It is an arithmetic number, because the mean of its divisors is an integer number (6746537805).

It is a Poulet number, since it divides 2^26985815896-1.

Almost surely, 2^26985815897 is an apocalyptic number.

26985815897 is the 134129-th pentagonal number.

It is an amenable number.

26985815897 is a deficient number, since it is larger than the sum of its proper divisors (335323).

26985815897 is a wasteful number, since it uses less digits than its factorization.

26985815897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 335322.

The product of its digits is 87091200, while the sum is 68.

The spelling of 26985815897 in words is "twenty-six billion, nine hundred eighty-five million, eight hundred fifteen thousand, eight hundred ninety-seven".