686816617536 has 189 divisors, whose sum is σ = 2290510080261. Its totient is φ = 196193539584.

The previous prime is 686816617477. The next prime is 686816617573. The reversal of 686816617536 is 635716618686.

The square root of 686816617536 is 828744.

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

686816617536 is a `hidden beast` number, since 6 + 8 + 6 + 8 + 1 + 6 + 617 + 5 + 3 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 214220865600 + 472595751936 = 462840^2 + 687456^2 .

It is a super-2 number, since 2×686816617536² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 139226526 + ... + 139231458.

Almost surely, 2^686816617536 is an apocalyptic number.

686816617536 is the 828744-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 686816617536

686816617536 is an abundant number, since it is smaller than the sum of its proper divisors (1603693462725).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

686816617536 is an frugal number, since it uses more digits than its factorization.

686816617536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9898 (or 4945 counting only the distinct ones).

The product of its digits is 52254720, while the sum is 63.

The spelling of 686816617536 in words is "six hundred eighty-six billion, eight hundred sixteen million, six hundred seventeen thousand, five hundred thirty-six".