686684655 has 48 divisors (see below), whose sum is σ = 1294950240. Its totient is φ = 344058624.

The previous prime is 686684653. The next prime is 686684659. The reversal of 686684655 is 556486686.

It is a happy number.

It is not a de Polignac number, because 686684655 - 2¹ = 686684653 is a prime.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686684653) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1255092 + ... + 1255638.

It is an arithmetic number, because the mean of its divisors is an integer number (26978130).

Almost surely, 2^686684655 is an apocalyptic number.

686684655 is a deficient number, since it is larger than the sum of its proper divisors (608265585).

686684655 is an equidigital number, since it uses as much as digits as its factorization.

686684655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1125 (or 572 counting only the distinct ones).

The product of its digits is 8294400, while the sum is 54.

The square root of 686684655 is about 26204.6685726036. The cubic root of 686684655 is about 882.2380425564.

The spelling of 686684655 in words is "six hundred eighty-six million, six hundred eighty-four thousand, six hundred fifty-five".