686387520 has 672 divisors, whose sum is σ = 3044391168. Its totient is φ = 143327232.

The previous prime is 686387503. The next prime is 686387539. The reversal of 686387520 is 25783686.

686387520 is a `hidden beast` number, since 6 + 8 + 638 + 7 + 5 + 2 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (672).

It is a super-2 number, since 2×686387520² = 942255655223500800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 7076112 + ... + 7076208.

It is an arithmetic number, because the mean of its divisors is an integer number (4530344).

Almost surely, 2^686387520 is an apocalyptic number.

686387520 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 686387520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1522195584).

686387520 is an abundant number, since it is smaller than the sum of its proper divisors (2358003648).

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

686387520 is a wasteful number, since it uses less digits than its factorization.

686387520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149 (or 127 counting only the distinct ones).

The product of its (nonzero) digits is 483840, while the sum is 45.

The square root of 686387520 is about 26198.9984541394. The cubic root of 686387520 is about 882.1107732591.

The spelling of 686387520 in words is "six hundred eighty-six million, three hundred eighty-seven thousand, five hundred twenty".