865687680 has 384 divisors, whose sum is σ = 3515279040. Its totient is φ = 193536000.

The previous prime is 865687663. The next prime is 865687687. The reversal of 865687680 is 86786568.

865687680 is a `hidden beast` number, since 8 + 6 + 568 + 76 + 8 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is not an unprimeable number, because it can be changed into a prime (865687687) 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, 823155 + ... + 824205.

Almost surely, 2^865687680 is an apocalyptic number.

865687680 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 865687680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1757639520).

865687680 is an abundant number, since it is smaller than the sum of its proper divisors (2649591360).

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

865687680 is a wasteful number, since it uses less digits than its factorization.

865687680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1100 (or 1085 counting only the distinct ones).

The product of its (nonzero) digits is 3870720, while the sum is 54.

The square root of 865687680 is about 29422.5709277758. The cubic root of 865687680 is about 953.0603725131.

The spelling of 865687680 in words is "eight hundred sixty-five million, six hundred eighty-seven thousand, six hundred eighty".