686593840 has 20 divisors (see below), whose sum is σ = 1596330864. Its totient is φ = 274637504.

The previous prime is 686593801. The next prime is 686593847. The reversal of 686593840 is 48395686.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-2 number, since 2×686593840² = 942822202251891200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (686593847) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4291132 + ... + 4291291.

Almost surely, 2^686593840 is an apocalyptic number.

It is an amenable number.

686593840 is an abundant number, since it is smaller than the sum of its proper divisors (909737024).

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

686593840 is a wasteful number, since it uses less digits than its factorization.

686593840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8582436 (or 8582430 counting only the distinct ones).

The product of its (nonzero) digits is 1244160, while the sum is 49.

The square root of 686593840 is about 26202.9357133891. The cubic root of 686593840 is about 882.1991484393.

The spelling of 686593840 in words is "six hundred eighty-six million, five hundred ninety-three thousand, eight hundred forty".