684086821 has 8 divisors (see below), whose sum is σ = 766446624. Its totient is φ = 605088720.

The previous prime is 684086813. The next prime is 684086839. The reversal of 684086821 is 128680486.

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 684086821 - 2³ = 684086813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (684086521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 839995 + ... + 840808.

It is an arithmetic number, because the mean of its divisors is an integer number (95805828).

Almost surely, 2^684086821 is an apocalyptic number.

It is an amenable number.

684086821 is a deficient number, since it is larger than the sum of its proper divisors (82359803).

684086821 is a wasteful number, since it uses less digits than its factorization.

684086821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1680851.

The product of its (nonzero) digits is 147456, while the sum is 43.

The square root of 684086821 is about 26155.0534505284. The cubic root of 684086821 is about 881.1240890747.

The spelling of 684086821 in words is "six hundred eighty-four million, eighty-six thousand, eight hundred twenty-one".