686657881 has 16 divisors (see below), whose sum is σ = 849429504. Its totient is φ = 540517824.

The previous prime is 686657879. The next prime is 686657957. The reversal of 686657881 is 188756686.

686657881 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 686657881 - 2¹ = 686657879 is a prime.

It is a super-2 number, since 2×686657881² = 942998091078820322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (686657831) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1225 + ... + 37078.

It is an arithmetic number, because the mean of its divisors is an integer number (53089344).

Almost surely, 2^686657881 is an apocalyptic number.

It is an amenable number.

686657881 is a deficient number, since it is larger than the sum of its proper divisors (162771623).

686657881 is a wasteful number, since it uses less digits than its factorization.

686657881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38520.

The product of its digits is 3870720, while the sum is 55.

The square root of 686657881 is about 26204.1577044560. The cubic root of 686657881 is about 882.2265761828.

The spelling of 686657881 in words is "six hundred eighty-six million, six hundred fifty-seven thousand, eight hundred eighty-one".