686655972 has 72 divisors (see below), whose sum is σ = 1830716160. Its totient is φ = 216406080.

The previous prime is 686655883. The next prime is 686656021. The reversal of 686655972 is 279556686.

It is a happy number.

686655972 is a `hidden beast` number, since 6 + 86 + 6 + 559 + 7 + 2 = 666.

686655972 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 677338 + ... + 678350.

Almost surely, 2^686655972 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 686655972, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (915358080).

686655972 is an abundant number, since it is smaller than the sum of its proper divisors (1144060188).

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

686655972 is a wasteful number, since it uses less digits than its factorization.

686655972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2033 (or 2028 counting only the distinct ones).

The product of its digits is 5443200, while the sum is 54.

The square root of 686655972 is about 26204.1212789134. The cubic root of 686655972 is about 882.2257586131.

The spelling of 686655972 in words is "six hundred eighty-six million, six hundred fifty-five thousand, nine hundred seventy-two".