685871121 has 12 divisors (see below), whose sum is σ = 990252528. Its totient is φ = 422074224.

The previous prime is 685871119. The next prime is 685871167. The reversal of 685871121 is 121178586.

It is not a de Polignac number, because 685871121 - 2¹ = 685871119 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a self number, because there is not a number n which added to its sum of digits gives 685871121.

It is not an unprimeable number, because it can be changed into a prime (685871111) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 675895 + ... + 676908.

It is an arithmetic number, because the mean of its divisors is an integer number (82521044).

Almost surely, 2^685871121 is an apocalyptic number.

It is an amenable number.

685871121 is a deficient number, since it is larger than the sum of its proper divisors (304381407).

685871121 is a wasteful number, since it uses less digits than its factorization.

685871121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1352832 (or 1352819 counting only the distinct ones).

The product of its digits is 26880, while the sum is 39.

The square root of 685871121 is about 26189.1412803093. The cubic root of 685871121 is about 881.8895010711.

The spelling of 685871121 in words is "six hundred eighty-five million, eight hundred seventy-one thousand, one hundred twenty-one".