685639539 has 32 divisors (see below), whose sum is σ = 1103995200. Its totient is φ = 418037760.

The previous prime is 685639501. The next prime is 685639543. The reversal of 685639539 is 935936586.

It is not a de Polignac number, because 685639539 - 2⁷ = 685639411 is a prime.

It is not an unprimeable number, because it can be changed into a prime (685639589) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 29299 + ... + 47219.

It is an arithmetic number, because the mean of its divisors is an integer number (34499850).

Almost surely, 2^685639539 is an apocalyptic number.

685639539 is a deficient number, since it is larger than the sum of its proper divisors (418355661).

685639539 is a wasteful number, since it uses less digits than its factorization.

685639539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18052 (or 18046 counting only the distinct ones).

The product of its digits is 5248800, while the sum is 54.

The square root of 685639539 is about 26184.7195707726. The cubic root of 685639539 is about 881.7902342563.

The spelling of 685639539 in words is "six hundred eighty-five million, six hundred thirty-nine thousand, five hundred thirty-nine".