686048640 has 128 divisors (see below), whose sum is σ = 2214950400. Its totient is φ = 180590592.

The previous prime is 686048611. The next prime is 686048663. The reversal of 686048640 is 46840686.

It is a tau number, because it is divible by the number of its divisors (128).

It is a junction number, because it is equal to n+sod(n) for n = 686048592 and 686048601.

It is a congruent number.

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, 149419 + ... + 153941.

It is an arithmetic number, because the mean of its divisors is an integer number (17304300).

Almost surely, 2^686048640 is an apocalyptic number.

686048640 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 686048640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1107475200).

686048640 is an abundant number, since it is smaller than the sum of its proper divisors (1528901760).

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

686048640 is a wasteful number, since it uses less digits than its factorization.

686048640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4624 (or 4612 counting only the distinct ones).

The product of its (nonzero) digits is 221184, while the sum is 42.

The square root of 686048640 is about 26192.5302328736. The cubic root of 686048640 is about 881.9655788419.

The spelling of 686048640 in words is "six hundred eighty-six million, forty-eight thousand, six hundred forty".