26661716566 has 4 divisors (see below), whose sum is σ = 39992574852. Its totient is φ = 13330858282.

The previous prime is 26661716531. The next prime is 26661716591. The reversal of 26661716566 is 66561716662.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6665429140 + ... + 6665429143.

It is an arithmetic number, because the mean of its divisors is an integer number (9998143713).

Almost surely, 2^26661716566 is an apocalyptic number.

26661716566 is a deficient number, since it is larger than the sum of its proper divisors (13330858286).

26661716566 is a wasteful number, since it uses less digits than its factorization.

26661716566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13330858285.

The product of its digits is 3265920, while the sum is 52.

The spelling of 26661716566 in words is "twenty-six billion, six hundred sixty-one million, seven hundred sixteen thousand, five hundred sixty-six".