26708431691 has 4 divisors (see below), whose sum is σ = 26730379032. Its totient is φ = 26686484352.

The previous prime is 26708431663. The next prime is 26708431693. The reversal of 26708431691 is 19613480762.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 26708431691 - 2¹⁸ = 26708169547 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (26708431693) 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, 10971845 + ... + 10974278.

It is an arithmetic number, because the mean of its divisors is an integer number (6682594758).

Almost surely, 2^26708431691 is an apocalyptic number.

26708431691 is a deficient number, since it is larger than the sum of its proper divisors (21947341).

26708431691 is a wasteful number, since it uses less digits than its factorization.

26708431691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21947340.

The product of its (nonzero) digits is 435456, while the sum is 47.

The spelling of 26708431691 in words is "twenty-six billion, seven hundred eight million, four hundred thirty-one thousand, six hundred ninety-one".