685639679 has 8 divisors (see below), whose sum is σ = 725020800. Its totient is φ = 647337600.

The previous prime is 685639651. The next prime is 685639693. The reversal of 685639679 is 976936586.

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 685639679 - 2¹⁶ = 685574143 is a prime.

It is a super-4 number, since 4×685639679⁴ (a number of 36 digits) contains 4444 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685639639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 268454 + ... + 270995.

It is an arithmetic number, because the mean of its divisors is an integer number (90627600).

Almost surely, 2^685639679 is an apocalyptic number.

685639679 is a deficient number, since it is larger than the sum of its proper divisors (39381121).

685639679 is a wasteful number, since it uses less digits than its factorization.

685639679 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 539521.

The product of its digits is 14696640, while the sum is 59.

The square root of 685639679 is about 26184.7222440873. The cubic root of 685639679 is about 881.7902942736.

The spelling of 685639679 in words is "six hundred eighty-five million, six hundred thirty-nine thousand, six hundred seventy-nine".