686699840 has 28 divisors (see below), whose sum is σ = 1635204756. Its totient is φ = 274679808.

The previous prime is 686699813. The next prime is 686699851. The reversal of 686699840 is 48996686.

It can be written as a sum of positive squares in 2 ways, for example, as 226683136 + 460016704 = 15056^2 + 21448^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1072649 + ... + 1073288.

Almost surely, 2^686699840 is an apocalyptic number.

It is an amenable number.

686699840 is an abundant number, since it is smaller than the sum of its proper divisors (948504916).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

686699840 is a wasteful number, since it uses less digits than its factorization.

686699840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2145954 (or 2145944 counting only the distinct ones).

The product of its (nonzero) digits is 4478976, while the sum is 56.

The square root of 686699840 is about 26204.9583094498. The cubic root of 686699840 is about 882.2445456316.

The spelling of 686699840 in words is "six hundred eighty-six million, six hundred ninety-nine thousand, eight hundred forty".