686139552 has 288 divisors, whose sum is σ = 2453371200. Its totient is φ = 185504256.

The previous prime is 686139541. The next prime is 686139583. The reversal of 686139552 is 255931686.

686139552 is a `hidden beast` number, since 6 + 8 + 61 + 39 + 552 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a junction number, because it is equal to n+sod(n) for n = 686139498 and 686139507.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 803958 + ... + 804810.

It is an arithmetic number, because the mean of its divisors is an integer number (8518650).

Almost surely, 2^686139552 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 686139552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1226685600).

686139552 is an abundant number, since it is smaller than the sum of its proper divisors (1767231648).

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

686139552 is a wasteful number, since it uses less digits than its factorization.

686139552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 905 (or 884 counting only the distinct ones).

The product of its digits is 388800, while the sum is 45.

The square root of 686139552 is about 26194.2656320043. The cubic root of 686139552 is about 882.0045351241.

The spelling of 686139552 in words is "six hundred eighty-six million, one hundred thirty-nine thousand, five hundred fifty-two".