687721860 has 384 divisors, whose sum is σ = 2580480000. Its totient is φ = 151901568.

The previous prime is 687721843. The next prime is 687721871. The reversal of 687721860 is 68127786.

It is a super-2 number, since 2×687721860² = 945922713443719200, 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 127 ways as a sum of consecutive naturals, for example, 8705301 + ... + 8705379.

It is an arithmetic number, because the mean of its divisors is an integer number (6720000).

Almost surely, 2^687721860 is an apocalyptic number.

687721860 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 687721860, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1290240000).

687721860 is an abundant number, since it is smaller than the sum of its proper divisors (1892758140).

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

687721860 is a wasteful number, since it uses less digits than its factorization.

687721860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165 (or 143 counting only the distinct ones).

The product of its (nonzero) digits is 225792, while the sum is 45.

The square root of 687721860 is about 26224.4515671920. The cubic root of 687721860 is about 882.6820121763.

The spelling of 687721860 in words is "six hundred eighty-seven million, seven hundred twenty-one thousand, eight hundred sixty".