686477721609 has 24 divisors (see below), whose sum is σ = 1003663507392. Its totient is φ = 452075833440.

The previous prime is 686477721577. The next prime is 686477721661. The reversal of 686477721609 is 906127774686.

686477721609 is a `hidden beast` number, since 6 + 86 + 477 + 7 + 21 + 60 + 9 = 666.

It is not a de Polignac number, because 686477721609 - 2⁵ = 686477721577 is a prime.

It is not an unprimeable number, because it can be changed into a prime (686477721509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5735244 + ... + 5853714.

It is an arithmetic number, because the mean of its divisors is an integer number (41819312808).

Almost surely, 2^686477721609 is an apocalyptic number.

It is an amenable number.

686477721609 is a deficient number, since it is larger than the sum of its proper divisors (317185785783).

686477721609 is a wasteful number, since it uses less digits than its factorization.

686477721609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126317 (or 126314 counting only the distinct ones).

The product of its (nonzero) digits is 42674688, while the sum is 63.

The spelling of 686477721609 in words is "six hundred eighty-six billion, four hundred seventy-seven million, seven hundred twenty-one thousand, six hundred nine".