686526587761 has 27 divisors (see below), whose sum is σ = 818849631627. Its totient is φ = 573900032160.

The previous prime is 686526587711. The next prime is 686526587797. The reversal of 686526587761 is 167785625686.

The square root of 686526587761 is 828569.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 33080698161 + 653445889600 = 181881^2 + 808360^2 .

It is not a de Polignac number, because 686526587761 - 2¹³ = 686526579569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (686526587711) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 237797860 + ... + 237800746.

Almost surely, 2^686526587761 is an apocalyptic number.

686526587761 is the 828569-th square number.

686526587761 is the 414285-th centered octagonal number.

It is an amenable number.

686526587761 is a deficient number, since it is larger than the sum of its proper divisors (132323043866).

686526587761 is an frugal number, since it uses more digits than its factorization.

686526587761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5870 (or 2935 counting only the distinct ones).

The product of its digits is 203212800, while the sum is 67.

The spelling of 686526587761 in words is "six hundred eighty-six billion, five hundred twenty-six million, five hundred eighty-seven thousand, seven hundred sixty-one".