686988656640 has 1360 divisors, whose sum is σ = 2909537126496. Its totient is φ = 152882380800.

The previous prime is 686988656591. The next prime is 686988656647. The reversal of 686988656640 is 46656889686.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686988656647) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 3795517350 + ... + 3795517530.

Almost surely, 2^686988656640 is an apocalyptic number.

686988656640 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 686988656640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1454768563248).

686988656640 is an abundant number, since it is smaller than the sum of its proper divisors (2222548469856).

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

686988656640 is a wasteful number, since it uses less digits than its factorization.

686988656640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254 (or 215 counting only the distinct ones).

The product of its (nonzero) digits is 716636160, while the sum is 72.

The spelling of 686988656640 in words is "six hundred eighty-six billion, nine hundred eighty-eight million, six hundred fifty-six thousand, six hundred forty".