686191964878 has 16 divisors (see below), whose sum is σ = 1176340682880. Its totient is φ = 294079370616.

The previous prime is 686191964851. The next prime is 686191964879. The reversal of 686191964878 is 878469191686.

It is a self number, because there is not a number n which added to its sum of digits gives 686191964878.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686191964879) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1857393 + ... + 2195971.

It is an arithmetic number, because the mean of its divisors is an integer number (73521292680).

Almost surely, 2^686191964878 is an apocalyptic number.

686191964878 is a deficient number, since it is larger than the sum of its proper divisors (490148718002).

686191964878 is a wasteful number, since it uses less digits than its factorization.

686191964878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 483351.

The product of its digits is 250822656, while the sum is 73.

The spelling of 686191964878 in words is "six hundred eighty-six billion, one hundred ninety-one million, nine hundred sixty-four thousand, eight hundred seventy-eight".