684200878561 has 8 divisors (see below), whose sum is σ = 684582201864. Its totient is φ = 683819642880.

The previous prime is 684200878541. The next prime is 684200878591. The reversal of 684200878561 is 165878002486.

It can be written as a sum of positive squares in 4 ways, for example, as 129146078161 + 555054800400 = 359369^2 + 745020^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 684200878561 - 2²⁷ = 684066660833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (684200878541) 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, 20822401 + ... + 20855233.

It is an arithmetic number, because the mean of its divisors is an integer number (85572775233).

Almost surely, 2^684200878561 is an apocalyptic number.

It is an amenable number.

684200878561 is a deficient number, since it is larger than the sum of its proper divisors (381323303).

684200878561 is a wasteful number, since it uses less digits than its factorization.

684200878561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43811.

The product of its (nonzero) digits is 5160960, while the sum is 55.

The spelling of 684200878561 in words is "six hundred eighty-four billion, two hundred million, eight hundred seventy-eight thousand, five hundred sixty-one".