687536640 has 640 divisors, whose sum is σ = 2946240000. Its totient is φ = 151732224.

The previous prime is 687536621. The next prime is 687536657. The reversal of 687536640 is 46635786.

It is a tau number, because it is divible by the number of its divisors (640).

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 63 ways as a sum of consecutive naturals, for example, 23708146 + ... + 23708174.

It is an arithmetic number, because the mean of its divisors is an integer number (4603500).

Almost surely, 2^687536640 is an apocalyptic number.

687536640 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 687536640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1473120000).

687536640 is an abundant number, since it is smaller than the sum of its proper divisors (2258703360).

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

687536640 is an equidigital number, since it uses as much as digits as its factorization.

687536640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82 (or 46 counting only the distinct ones).

The product of its (nonzero) digits is 725760, while the sum is 45.

The square root of 687536640 is about 26220.9198923302. The cubic root of 687536640 is about 882.6027625788.

The spelling of 687536640 in words is "six hundred eighty-seven million, five hundred thirty-six thousand, six hundred forty".