686137505520 has 320 divisors, whose sum is σ = 2239925207040. Its totient is φ = 173529907200.

The previous prime is 686137505519. The next prime is 686137505587. The reversal of 686137505520 is 25505731686.

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 686137505520.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 80518860 + ... + 80527380.

It is an arithmetic number, because the mean of its divisors is an integer number (6999766272).

Almost surely, 2^686137505520 is an apocalyptic number.

686137505520 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 686137505520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1119962603520).

686137505520 is an abundant number, since it is smaller than the sum of its proper divisors (1553787701520).

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

686137505520 is a wasteful number, since it uses less digits than its factorization.

686137505520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8784 (or 8778 counting only the distinct ones).

The product of its (nonzero) digits is 1512000, while the sum is 48.

The spelling of 686137505520 in words is "six hundred eighty-six billion, one hundred thirty-seven million, five hundred five thousand, five hundred twenty".