687521128 has 64 divisors (see below), whose sum is σ = 1516475520. Its totient is φ = 286080000.

The previous prime is 687521119. The next prime is 687521147. The reversal of 687521128 is 821125786.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 575700 + ... + 576892.

It is an arithmetic number, because the mean of its divisors is an integer number (23694930).

Almost surely, 2^687521128 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 687521128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (758237760).

687521128 is an abundant number, since it is smaller than the sum of its proper divisors (828954392).

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

687521128 is a wasteful number, since it uses less digits than its factorization.

687521128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1498 (or 1494 counting only the distinct ones).

The product of its digits is 53760, while the sum is 40.

The square root of 687521128 is about 26220.6240963101. The cubic root of 687521128 is about 882.5961248540.

The spelling of 687521128 in words is "six hundred eighty-seven million, five hundred twenty-one thousand, one hundred twenty-eight".