684064821 has 16 divisors (see below), whose sum is σ = 1011870720. Its totient is φ = 407556720.

The previous prime is 684064813. The next prime is 684064831. The reversal of 684064821 is 128460486.

It is not a de Polignac number, because 684064821 - 2³ = 684064813 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 684064821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (684064831) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 173725 + ... + 177618.

It is an arithmetic number, because the mean of its divisors is an integer number (63241920).

Almost surely, 2^684064821 is an apocalyptic number.

It is an amenable number.

684064821 is a deficient number, since it is larger than the sum of its proper divisors (327805899).

684064821 is a wasteful number, since it uses less digits than its factorization.

684064821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 351416.

The product of its (nonzero) digits is 73728, while the sum is 39.

The square root of 684064821 is about 26154.6328783258. The cubic root of 684064821 is about 881.1146434229.

The spelling of 684064821 in words is "six hundred eighty-four million, sixty-four thousand, eight hundred twenty-one".