684385778 has 8 divisors (see below), whose sum is σ = 1026700272. Its totient is φ = 342152356.

The previous prime is 684385777. The next prime is 684385783. The reversal of 684385778 is 877583486.

It is a happy number.

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

It is a super-3 number, since 3×684385778³ (a number of 27 digits) contains 333 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (684385777) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9701 + ... + 38247.

It is an arithmetic number, because the mean of its divisors is an integer number (128337534).

Almost surely, 2^684385778 is an apocalyptic number.

684385778 is a deficient number, since it is larger than the sum of its proper divisors (342314494).

684385778 is a wasteful number, since it uses less digits than its factorization.

684385778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40536.

The product of its digits is 9031680, while the sum is 56.

The square root of 684385778 is about 26160.7679168636. The cubic root of 684385778 is about 881.2524255387.

The spelling of 684385778 in words is "six hundred eighty-four million, three hundred eighty-five thousand, seven hundred seventy-eight".