686191964881 has 6 divisors (see below), whose sum is σ = 694987894482. Its totient is φ = 677505984480.

The previous prime is 686191964879. The next prime is 686191964891. The reversal of 686191964881 is 188469191686.

It can be written as a sum of positive squares in only one way, i.e., 591460974225 + 94730990656 = 769065^2 + 307784^2 .

It is not a de Polignac number, because 686191964881 - 2¹ = 686191964879 is a prime.

It is a super-2 number, since 2×686191964881² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (686191964851) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 54968280 + ... + 54980761.

It is an arithmetic number, because the mean of its divisors is an integer number (115831315747).

Almost surely, 2^686191964881 is an apocalyptic number.

It is an amenable number.

686191964881 is a deficient number, since it is larger than the sum of its proper divisors (8795929601).

686191964881 is an equidigital number, since it uses as much as digits as its factorization.

686191964881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109949199 (or 109949120 counting only the distinct ones).

The product of its digits is 35831808, while the sum is 67.

The spelling of 686191964881 in words is "six hundred eighty-six billion, one hundred ninety-one million, nine hundred sixty-four thousand, eight hundred eighty-one".