686871840 has 96 divisors (see below), whose sum is σ = 2172272256. Its totient is φ = 182435840.

The previous prime is 686871827. The next prime is 686871853. The reversal of 686871840 is 48178686.

It is an interprime number because it is at equal distance from previous prime (686871827) and next prime (686871853).

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 686871840.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 123520 + ... + 128960.

It is an arithmetic number, because the mean of its divisors is an integer number (22627836).

Almost surely, 2^686871840 is an apocalyptic number.

686871840 is a gapful number since it is divisible by the number (60) 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 686871840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1086136128).

686871840 is an abundant number, since it is smaller than the sum of its proper divisors (1485400416).

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

686871840 is a wasteful number, since it uses less digits than its factorization.

686871840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5722 (or 5714 counting only the distinct ones).

The product of its (nonzero) digits is 516096, while the sum is 48.

The square root of 686871840 is about 26208.2399256417. The cubic root of 686871840 is about 882.3181990608.

The spelling of 686871840 in words is "six hundred eighty-six million, eight hundred seventy-one thousand, eight hundred forty".