687721500 has 144 divisors (see below), whose sum is σ = 2202878496. Its totient is φ = 180576000.

The previous prime is 687721499. The next prime is 687721547. The reversal of 687721500 is 5127786.

687721500 is a `hidden beast` number, since 6 + 87 + 72 + 1 + 500 = 666.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 300360 + ... + 302640.

Almost surely, 2^687721500 is an apocalyptic number.

687721500 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 687721500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1101439248).

687721500 is an abundant number, since it is smaller than the sum of its proper divisors (1515156996).

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

687721500 is a wasteful number, since it uses less digits than its factorization.

687721500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2373 (or 2358 counting only the distinct ones).

The product of its (nonzero) digits is 23520, while the sum is 36.

The square root of 687721500 is about 26224.4447033679. Note that the first 3 decimals coincide. The cubic root of 687721500 is about 882.6818581578.

The spelling of 687721500 in words is "six hundred eighty-seven million, seven hundred twenty-one thousand, five hundred".