684317639 has 4 divisors (see below), whose sum is σ = 684498024. Its totient is φ = 684137256.

The previous prime is 684317629. The next prime is 684317657. The reversal of 684317639 is 936713486.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 684317639 - 2¹² = 684313543 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 684317593 and 684317602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (684317629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 84377 + ... + 92130.

It is an arithmetic number, because the mean of its divisors is an integer number (171124506).

Almost surely, 2^684317639 is an apocalyptic number.

684317639 is a deficient number, since it is larger than the sum of its proper divisors (180385).

684317639 is a wasteful number, since it uses less digits than its factorization.

684317639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180384.

The product of its digits is 653184, while the sum is 47.

The square root of 684317639 is about 26159.4655717582. The cubic root of 684317639 is about 881.2231780714.

The spelling of 684317639 in words is "six hundred eighty-four million, three hundred seventeen thousand, six hundred thirty-nine".